How many feathers, traditionally, form the cone of a badminton shuttlecock?
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Feather Badminton Shuttlecock
Feathers are epidermal growths that form the distinctive outer covering, or plumage, on coelurosaurian dinosaurs. They are considered the most complex integumentary structures found in vertebrates,  and indeed a premier example of a complex evolutionary novelty. They are among the characteristics that distinguish the extant Aves from other living groups. 

Although feathers cover most parts of the body of birds, they arise only from certain well-defined tracts on the skin. They aid in flight, thermal insulation, and waterproofing. In addition, coloration helps in communication and protection. Plumology (or plumage science) is the name for the science that is associated with the study of feathers.

Structures and characteristics

Feathers are among the most complex integumentary appendages found in vertebrates and are formed in tiny follicles in the epidermis, or outer skin layer, that produce keratin proteins. The β-keratins in feathers, beaks and claws — and the claws, scales and shells of reptiles — are composed of protein strands hydrogen-bonded into β-pleated sheets, which are then further twisted and crosslinked by disulfide bridges into structures even tougher than the α-keratins of mammalian hair, horns and hoof.   The exact signals that induce the growth of feathers on the skin are not known, but it has been found that the transcription factor cDermo-1 induces the growth of feathers on skin and scales on the leg. 

Classification

There are two basic types of feather: vaned feathers which cover the exterior of the body, and down feathers which are underneath the vaned feathers. The pennaceous feathers are vaned feathers. Also called contour feathers, pennaceous feathers arise from tracts and cover the entire body. A third rarer type of feather, the filoplume, is hairlike and (if present in a bird; they are entirely absent in ratites ) grows along the fluffy down feathers. In some passerines, filoplumes arise exposed beyond the contour feathers on the neck. The remiges, or flight feathers of the wing, and rectrices, the flight feathers of the tail are the most important feathers for flight. A typical vaned feather features a main shaft, called the rachis. Fused to the rachis are a series of branches, or barbs; the barbs themselves are also branched and form the barbules. These barbules have minute hooks called barbicels for cross-attachment. Down feathers are fluffy because they lack barbicels, so the barbules float free of each other, allowing the down to trap air and provide excellent thermal insulation. At the base of the feather, the rachis expands to form the hollow tubular calamus (or quill) which inserts into a follicle in the skin. The basal part of the calamus is without vanes. This part is embedded within the skin follicle and has an opening at the base (proximal umbilicus) and a small opening on the side (distal umbilicus).

Hatchling birds of some species have a special kind of natal down feathers (neossoptiles) which are pushed out when the normal feathers (teleoptiles) emerge.

Flight feathers are stiffened so as to work against the air in the downstroke but yield in other directions. It has been observed that the orientation pattern of β-keratin fibers in the feathers of flying birds differs from that in flightless birds: the fibers are better aligned in the middle of the feather and less aligned towards the tips.  

Functions

Feathers insulate birds from water and cold temperatures. They may also be plucked to line the nest and provide insulation to the eggs and young. The individual feathers in the wings and tail play important roles in controlling flight. Some species have a crest of feathers on their heads. Although feathers are light, a bird's plumage weighs two or three times more than its skeleton, since many bones are hollow and contain air sacs. Color patterns serve as camouflage against predators for birds in their habitats, and serve as camouflage for predators looking for a meal. As with fish, the top and bottom colors may be different, in order to provide camouflage during flight. Striking differences in feather patterns and colors are part of the sexual dimorphism of many bird species and are particularly important in selection of mating pairs. In some cases there are differences in the UV reflectivity of feathers across sexes even though no differences in color are noted in the visible range.  The wing feathers of male club-winged manakins Machaeropterus deliciosus have special structures that are used to produce sounds by stridulation. 

Some birds have a supply of powder down feathers which grow continuously, with small particles regularly breaking off from the ends of the barbules. These particles produce a powder that sifts through the feathers on the bird's body and acts as a waterproofing agent and a feather conditioner. Powder down has evolved independently in several taxa and can be found in down as well as in pennaceous feathers. They may be scattered in plumage as in the pigeons and parrots or in localized patches on the breast, belly, or flanks, as in herons and frogmouths. Herons use their bill to break the powder down feathers and to spread them, while cockatoos may use their head as a powder puff to apply the powder. Waterproofing can be lost by exposure to emulsifying agents due to human pollution. Feathers can then become waterlogged, causing the bird to sink. It is also very difficult to clean and rescue birds whose feathers have been fouled by oil spills. The feathers of cormorants soak up water and help to reduce buoyancy, thereby allowing the birds to swim submerged. 

Bristles are stiff, tapering feathers with a large rachis but few barbs. Rictal bristles are found around the eyes and bill. They may serve a similar purpose to eyelashes and vibrissae in mammals. Although there is as yet no clear evidence, it has been suggested that rictal bristles have sensory functions and may help insectivorous birds to capture prey.  In one study, willow flycatchers (Empidonax traillii) were found to catch insects equally well before and after removal of the rictal bristles. 

Grebes are peculiar in their habit of ingesting their own feathers and feeding them to their young. Observations on their diet of fish and the frequency of feather eating suggest that ingesting feathers, particularly down from their flanks, aids in forming easily ejectable pellets. 

Distribution

Contour feathers are not uniformly distributed on the skin of the bird except in some groups such as the penguins, ratites and screamers.  In most birds the feathers grow from specific tracts of skin called pterylae; between the pterylae there are regions which are free of feathers called apterylae. Filoplumes and down may arise from the apterylae. The arrangement of these feather tracts, pterylosis or pterylography, varies across bird families and has been used in the past as a means for determining the evolutionary relationships of bird families.  

Coloration

The colors of feathers are produced by pigments, by microscopic structures that can refract, reflect, or scatter selected wavelengths of light, or by a combination of both.

Most feather pigments are melanins (brown and beige pheomelanins, black and grey eumelanins) and carotenoids (red, yellow, orange); other pigments occur only in certain taxa – the yellow to red psittacofulvins  (found in some parrots) and the red turacin and green turacoverdin (porphyrin pigments found only in turacos).

Structural coloration   is involved in the production of blue colors, iridescence, most ultraviolet reflectance and in the enhancement of pigmentary colors. Structural iridescence has been reported  in fossil feathers dating back 40 million years. White feathers lack pigment and scatter light diffusely; albinism in birds is caused by defective pigment production, though structural coloration will not be affected (as can be seen, for example, in blue-and-white budgerigars).

The blues and bright greens of many parrots are produced by constructive interference of light reflecting from different layers of structures in feathers.  In the case of green plumage, in addition to yellow, the specific feather structure involved is called by some the Dyck texture.   Melanin is often involved in the absorption of light; in combination with a yellow pigment, it produces a dull olive-green.

In some birds, feather colors may be created, or altered, by secretions from the uropygial gland, also called the preen gland. The yellow bill colors of many hornbills are produced by such secretions.  It has been suggested that there are other color differences that may be visible only in the ultraviolet region, but studies have failed to find evidence.  The oil secretion from the uropygial gland may also have an inhibitory effect on feather bacteria. 

Perhaps most interestingly, the reds, orange and yellow colors of many feathers are caused by various carotenoids. Carotenoid-based pigments might be honest signals of fitness because they are derived from special diets and hence might be difficult to obtain,   and/or because carotenoids are required for immune function and hence sexual displays come at the expense of health. 

A bird's feathers undergo wear and tear and are replaced periodically during the bird's life through molting. New feathers, known when developing as blood, or pin feathers, depending on the stage of growth, are formed through the same follicles from which the old ones were fledged. The presence of melanin in feathers increases their resistance to abrasion.  One study notes that melanin based feathers were observed to degrade more quickly under bacterial action, even compared to unpigmented feathers from the same species, than those unpigmented or with carotenoid pigments.  However, another study the same year compared the action of bacteria on pigmentations of two song sparrow species and observed that the darker pigmented feathers were more resistant; the authors cited other research also published in 2004 that stated increased melanin provided greater resistance.  They observed that the greater resistance of the darker birds confirmed Gloger's rule. 

Although sexual selection plays a major role in the development of feathers,in particular the color of the feathers it is not the only conclusion available. New studies are suggesting that the unique feathers of birds is also a large influence on many important aspects of avian behavior, such as the height at which a different species build their nests. Since females are the prime care giver, evolution has helped select females to display of duller colored down so that she may blend into her nesting environment.The position of the nest and whether it has a greater chance of being under predation has exerted constraints onto female bird’s plumage.  A species of bird that makes it nest on the ground, opposed to the canopy of the trees, will need to have much duller colors in order not to attract attention to the nest. Since the female is the main care giver in some species of birds, evolution has helped select traits that make her feathers dull and often allow her to blend into the surroundings. The height study found that birds that nest in the canopies of trees often have many more predator attacks due to the brighter color of feathers that the female displays. Another influence of evolution that could play a part in why feathers of birds are so colorful and display so many patterns could be due to that birds developed their bright colors from the vegetation and flowers that thrive around them. Birds develop their bright colors from living around certain colors. Most bird species often blend into their environment, due to some degree of camouflage, so if the species habitat is full of colors and patterns, the species would eventually evolve to blend in to avoid being eaten.  Bird’s feathers show a large range of colors, even exceeding the variety of many plants, leaf and flower colors. 

Parasites

The feather surface is the home for some ectoparasites, notably feather lice (Phthiraptera) and feather mites. Feather lice typically live on a single host and can move only from parents to chicks, between mating birds, and, occasionally, by phoresy. This life history has resulted in most of the parasite species being specific to the host and coevolving with the host, making them of interest in phylogenetic studies. 

Feather holes are chewing traces of lice (most probably Brueelia spp. lice) on the wing and tail feathers. They were described on barn swallows, and because of easy countability, many evolutionary, ecological, and behavioral publications use them to quantify the intensity of infestation.

Interestingly, parasitic cuckoos which grow up in the nests of other species also have host specific feather lice and these seem to be transmitted only after the young cuckoos leave the host nest. 

Birds maintain their feather condition by bathing in water, dust bathing, and preening. It has been suggested that a peculiar behavior of birds, anting, in which ants are introduced into the plumage, helps to reduce parasites, but no supporting evidence has been found. 

Human usage

Feathers have a number of utilitarian, cultural and religious uses.

Utilitarian functions

Feathers are both soft and excellent at trapping heat; thus, they are sometimes used in high-class bedding, especially pillows, blankets, and mattresses. They are also used as filling for winter clothing and outdoor bedding, such as quilted coats and sleeping bags. Goose and eider down have great loft, the ability to expand from a compressed, stored state to trap large amounts of compartmentalized, insulating air. 

Bird feathers have long been used for fletching arrows. Colorful feathers such as those belonging to pheasants have been used to decorate fishing lures.

Feathers of large birds (most often geese) have been and are used to make quill pens. The word pen itself is derived from the Latin penna, meaning feather.  The French word plume can mean either feather or pen.

Feathers are also valuable in aiding the identification of species in forensic studies, particularly in bird strikes to aircraft. The ratios of hydrogen isotopes in feathers help in determining the geographic origins of birds.  Feathers may also be useful in the non-destructive sampling of pollutants. 

The poultry industry produces a large amount of feathers as waste, and, like other forms of keratin, are slow to decompose. Feather waste has been used in a number of industrial applications as a medium for culturing microbes,  biodegradeable polymers,  and production of enzymes.  Feather proteins have been tried as an adhesive for wood board. 

Some groups of Native people in Alaska have used ptarmigan feathers as temper (non-plastic additives) in pottery manufacture since the first millennium BC in order to promote thermal shock resistance and strength. 

The hunting of birds for decorative and ornamental feathers (including in Victorian fashion) has endangered some species. For instance, South American hummingbird feathers were used in the past to dress some of the miniature birds featured in singing bird boxes.

In religion and culture

Eagle feathers have great cultural and spiritual value to American Indians in the US and  First Nations peoples in Canada as religious objects. In the United States the religious use of eagle and hawk feathers is governed by the eagle feather law, a federal law limiting the possession of eagle feathers to certified and enrolled members of federally recognized Native American tribes.

In South America, brews made from the feathers of condors are used in traditional medications.  In India, feathers of the Indian peacock have been used in traditional medicine for snakebite, infertility, and coughs.  

During the 18th, 19th, and early 20th centuries, there was a booming international trade in plumes for extravagant women's hats and other headgear.  Frank Chapman noted in 1886 that feathers of as many as 40 species of birds were used in about three-fourths of the 700 ladies' hats that he observed in New York City.  This trade caused severe losses to bird populations (for example, egrets and whooping cranes). Conservationists led a major campaign against the use of feathers in hats. This contributed to passage of the Lacey Act in 1900, and to changes in fashion. The ornamental feather market then largely collapses.  

More recently, rooster plumage has become a popular trend as a hairstyle accessory, with feathers formerly used as fishing lures now being used to provide color and style to hair.  Today, feathers used in fashion and in military headresses and clothes are obtained as a waste product of poultry farming, including chickens, geese, turkeys, pheasants, and ostriches. These feathers are dyed and manipulated to enhance their appearance, as  poultry feathers are naturally often dull in appearance compared to the feathers of wild birds.

Feather products manufacturing in Europe has declined in the last 60 years, mainly due to competition from Asia. 
Feathers have adorned hats at many prestigious events such as weddings and Ladies Day at race courses (Royal Ascot).

Evolution

The functional view on the evolution of feathers has traditionally focused on insulation, flight and display. Discoveries of non-flying Late Cretaceous feathered dinosaurs in China, however, suggest that flight could not have been the original primary function as the feathers simply would not have been capable of providing any form of lift.  There have been suggestions that feathers may have had their original function in thermoregulation, waterproofing, or even as sinks for metabolic wastes such as sulphur.  Recent discoveries are claimed to support a thermoregulatory function, at least in smaller dinosaurs.  While feathers have been suggested as having evolved from reptilian scales, there are numerous objections to that idea, and more recent explanations have arisen from the paradigm of evolutionary developmental biology. Theories of the scale-based origins of feathers suggest that the planar scale structure was modified for development into feathers by splitting to form the webbing; however, that developmental process involves a tubular structure arising from a follicle and the tube splitting longitudinally to form the webbing. The number of feathers per unit area of skin is higher in smaller birds than in larger birds, and this trend points to their important role in thermal insulation, since smaller birds lose more heat due to the relatively larger surface area in proportion to their body weight. The miniaturization of birds also played a role in the evolution of powered flight.  The coloration of feathers is believed to have evolved primarily in response to sexual selection. In one fossil specimen of the Parave Anchiornis huxleyi, the features are so well preserved that the melanosome (pigment cells) structure can be observed. By comparing the shape of the fossil melanosomes to melanosomes from extant birds, the color and pattern of the feathers on Anchiornis could be determined.  Anchiornis was found to have black and white patterned feathers on the forelimbs and hindlimbs, with a reddish brown crest. This pattern is similar to the coloration of many extant bird species, which use plumage coloration for display and communication, including sexual selection and camouflage. It is likely that non-avian dinosaur species utilized plumage patterns for similar functions as modern birds before the origin of flight. In many cases, the physiological condition of the birds (especially males) is indicated by the quality of their feathers, and this is used (by the females) in mate choice.  

Feathers and scales are made up of two distinct forms of keratin, and it was long thought that each type of keratin was exclusive to each skin structure (feathers and scales). However, a study published in 2006 confirmed the presence of feather keratin in the early stages of development of American alligator scales. This type of keratin, previously thought to be specific to feathers, is suppressed during embryological development of the alligator and so is not present in the scales of mature alligators. The presence of this homologous keratin in both birds and crocodilians indicates that it was inherited from a common ancestor. This may suggest that crocodilian scales, bird and dinosaur feathers, and pterosaur pycnofibres are all developmental expressions of the same primitive archosaur skin structures; suggesting that feathers and pycnofibers could be homologous. 

Feathered dinosaurs

Several non-avian dinosaurs had feathers on their limbs that would not have functioned for flight. One theory suggests that feathers originally evolved on dinosaurs as a result of their insulation properties; small dinosaur species that grew longer feathers may have found them helpful in gliding, leading to the evolution of  proto-birds like Archaeopteryx and Microraptor zhaoianus. Another theory posits that the original adaptive advantage of early feathers was their pigmentation or iridescence, contributing to sexual preference in mate selection.  Dinosaurs that had feathers or protofeathers include Pedopenna daohugouensis  and Dilong paradoxus, a tyrannosauroid which is 60 to 70 million years older than Tyrannosaurus rex. 

The majority of dinosaurs known to have had feathers or protofeathers are saurischians, however featherlike "filamentous integumentary structures" are also known from the ornithischians Tianyulong and Psittacosaurus.  The exact nature of these structures is still under study. However, it is believed that the stage-1 feathers (see Evolutionary stages section below) such as those seen in these two ornithischians likely functioned in display. In 2014, the ornithischian Kulindadromeus was reported as having structures resembling stage-3 feathers. 

Since the 1990s, dozens of feathered dinosaurs have been discovered in the clade Maniraptora, which includes the clade Avialae and the recent common ancestors of birds, Oviraptorosauria and Deinonychosauria. In 1998, the discovery of a feathered oviraptorosaurian, Caudipteryx zoui, challenged the notion of feathers as a structure exclusive to Avialae.   Buried in the Yixian Formation in Liaoning, China, C. zoui lived during the Early Cretaceous Period.  Present on the forelimbs and tails, their integumentary structure has been accepted as pennaceous vaned feathers based on the rachis and herringbone pattern of the barbs. In the clade Deinonychosauria, the continued divergence of feathers is also apparent in the families Troodontidae and Dromaeosauridae. Branched feathers with rachis, barbs, and barbules were discovered in many members including Sinornithosaurus millenii, a dromaeosaurid found in the Yixian formation (124.6 MYA). 

Previously, a temporal paradox existed in the evolution of feathers—theropods with highly derived bird-like characteristics occurred at a later time than Archaeopteryx—suggesting that the descendants of birds arose before the ancestor.  However, the discovery of Anchiornis huxleyi in the Late Jurassic Tiaojishan Formation (160 MYA) in western Liaoning in 2009  
resolved this paradox. By predating Archaeopteryx, Anchiornis proves the existence of a modernly feathered theropod ancestor, providing insight into the dinosaur-bird transition. The specimen shows distribution of large pennaceous feathers on the forelimbs and tail, implying that pennaceous feathers spread to the rest of the body at an earlier stage in theropod evolution.  The discovery, in 2011, of feathers preserved in amber, within samples dating to 80 mya, suggests the coexistence of theropods and birds, with both theropod and avian feather types commingled in the samples. 

Two 100 million wings trapped in amber show plumage existed in some bird predecessors, the wings probably were from enantiornithes.  

Evolutionary stages

Several studies of feather development in the embryos of modern birds, coupled with the distribution of feather types among various prehistoric bird precursors, have allowed scientists to attempt a reconstruction of the sequence in which feathers first evolved and developed into the types found on modern birds.

Feather evolution was broken down into the following stages by Xu and Guo in 2009: 
# Single filament
# Multiple filaments joined at their base
# Multiple filaments joined at their base to a central filament
# Multiple filaments along the length of a central filament
# Multiple filaments arising from the edge of a membranous structure
# Pennaceous feather with vane of barbs and barbules and central rachis
# Pennaceous feather with an asymmetrical rachis
# Undifferentiated vane with central rachis

However, Foth (2011) showed that some of these purported stages (stages 2 and 5 in particular) are likely simply artifacts of preservation caused by the way fossil feathers are crushed and the feather remains or imprints are preserved. Foth re-interpreted stage 2 feathers as crushed or misidentified feathers of at least stage 3, and stage 5 feathers as crushed stage 6 feathers. 

The following simplified diagram of dinosaur relationships follows these results, and shows the likely distribution of plumaceous (downy) and pennaceous (vaned) feathers among dinosaurs and prehistoric birds. The diagram follows one presented by Xu and Guo (2009) modified with the findings of Foth (2011). The numbers accompanying each name refer to the presence of specific feather stages. Note that 's' indicates the known presence of scales on the body. Badminton is a racquet sport played using racquets to hit a shuttlecock across a net. Although it may be played with larger teams, the most common forms of the game are "singles" (with one player per side) and "doubles" (with two players per side). Badminton is often played as a casual outdoor activity in a yard or on a beach; formal games are played on a rectangular indoor court. Points are scored by striking the shuttlecock with the racquet and landing it within the opposing side's half of the court. 

Each side may only strike the shuttlecock once before it passes over the net. Play ends once the shuttlecock has struck the floor or if a fault has been called by the umpire, service judge, or (in their absence) the opposing side.

The shuttlecock is a feathered or (in informal matches) plastic projectile which flies differently from the balls used in many other sports. In particular, the feathers create much higher drag, causing the shuttlecock to decelerate more rapidly. Shuttlecocks also have a high top speed compared to the balls in other racquet sports.

The game developed in British India from the earlier game of battledore and shuttlecock. European play came to be dominated by Denmark but the game has become very popular in Asia, with recent competition dominated by China. Since 1992, badminton has been a Summer Olympic sport with five events: men's singles, women's singles, men's doubles, women's doubles, and mixed doubles. At high levels of play, the sport demands excellent fitness: players require aerobic stamina, agility, strength, speed, and precision. It is also a technical sport, requiring good motor coordination and the development of sophisticated racquet movements.

History

Games employing shuttlecocks have been played for centuries across Eurasia but the modern game of badminton developed in the mid-19th century among the British as a variant of the earlier game of battledore and shuttlecock. ("Battledore" was an older term for "racquet".) Its exact origin remains obscure. The name derives from the Duke of Beaufort's Badminton House in Gloucestershire, but why or when remains unclear. As early as 1860, a London toy dealer named Isaac Spratt published a booklet titled Badminton Battledore—A New Game but unfortunately no copy has survived. An 1863 article in The Cornhill Magazine describes badminton as "battledore and shuttlecock played with sides, across a string suspended some five feet from the ground". 

The game may have originally developed among expatriate officers in British India, where it was very popular by the 1870s. Ball badminton, a form of the game played with a wool ball instead of a shuttlecock, was being played in Thanjavur as early as the 1850s and was at first played interchangeably with badminton by the British, the woollen ball being preferred in windy or wet weather.

Early on, the game was also known as Poona or Poonah after the garrison town of Pune, where it was particularly popular and where the first rules for the game were drawn up in 1873. By 1875, returning officers had started a badminton club in Folkestone. Initially, the sport was played with sides ranging from 1–4 players but it was quickly established that games between two or four competitors worked the best. The shuttlecocks were coated with India rubber and, in outdoor play, sometimes weighted with lead. Although the depth of the net was of no consequence, it was preferred that it should reach the ground. 

The sport was played under the Pune rules until 1887, when the J.H.E. Hart of the Bath Badminton Club drew up revised regulations. In 1890, Hart and Bagnel Wild again revised the rules. The Badminton Association of England published these rules in 1893 and officially launched the sport at a house called "Dunbar" in Portsmouth on 13 September. The BAE started the first badminton competition, the All England Open Badminton Championships for gentlemen's doubles, ladies' doubles, and mixed doubles, in 1899. Singles competitions were added in 1900 and an England—Ireland championship match appeared in 1904.

England, Scotland, Wales, Canada, Denmark, France, Ireland, the Netherlands, and New Zealand were the founding members of the International Badminton Federation in 1934, now known as the Badminton World Federation. India joined as an affiliate in 1936. The BWF now governs international badminton. Although initiated in England, competitive men's badminton has traditionally been dominated in Europe by Denmark. Worldwide, Asian nations have become dominant in international competition. China, Denmark, India, Indonesia, Malaysia, and South Korea are the nations which have consistently produced world-class players in the past few decades, with China being the greatest force in men's and women's competition recently.

Rules

The following information is a simplified summary of badminton rules based on the BWF Statutes publication, Laws of Badminton.

Court

The court is rectangular and divided into halves by a net. Courts are usually marked for both singles and doubles play, although badminton rules  permit a court to be marked for singles only.  The doubles court is wider than the singles court, but both are of same length. The exception, which often causes confusion to newer players, is that the doubles court has a shorter serve-length dimension.

The full width of the court is 6.1 metres (20 ft), and in singles this width is reduced to 5.18 metres (17 ft). The full length of the court is 13.4 metres (44 ft). The service courts are marked by a centre line dividing the width of the court, by a short service line at a distance of 1.98 metres (6 ft 6 inch) from the net, and by the outer side and back boundaries. In doubles, the service court is also marked by a long service line, which is 0.76 metres (2 ft 6 inch) from the back boundary.

The net is 1.55 metres (5 ft 1 inch) high at the edges and 1.524 metres (5 ft) high in the centre. The net posts are placed over the doubles sidelines, even when singles is played.

The minimum height for the ceiling above the court is not mentioned in the Laws of Badminton. Nonetheless, a badminton court will not be suitable if the ceiling is likely to be hit on a high serve.

Serving

When the server serves, the shuttlecock must pass over the short service line on the opponents' court or it will count as a fault.

At the start of the rally, the server and receiver stand in diagonally opposite service courts (see court dimensions). The server hits the shuttlecock so that it would land in the receiver's service court. This is similar to tennis, except that a badminton serve must be hit below waist height and with the racquet shaft pointing downwards, the shuttlecock is not allowed to bounce and in badminton, the players stand inside their service courts unlike tennis.

When the serving side loses a rally, the serve immediately passes to their opponent(s) (this differs from the old system where sometimes the serve passes to the doubles partner for what is known as a "second serve").

In singles, the server stands in their right service court when their score is even, and in her/his left service court when her/his score is odd.

In doubles, if the serving side wins a rally, the same player continues to serve, but he/she changes service courts so that she/he serves to a different opponent each time. If the opponents win the rally and their new score is even, the player in the right service court serves; if odd, the player in the left service court serves. The players' service courts are determined by their positions at the start of the previous rally, not by where they were standing at the end of the rally. A consequence of this system is that, each time a side regains the service, the server will be the player who did not serve last time.

Scoring

Each game is played to 21 points, with players scoring a point whenever they win a rally regardless of whether they served (this differs from the old system where players could only win a point on their serve and each game was played to 15 points). A match is the best of three games.

If the score reaches 20-all, then the game continues until one side gains a two-point lead (such as 24–22), except when there is a tie at 29-all, in which the game goes to a golden point. Whoever scores this point will win.

At the start of a match, the shuttlecock is cast and the side towards which the shuttlecock is pointing serves first. Alternatively, a coin may be tossed, with the winners choosing whether to serve or receive first, or choosing which end of the court to occupy first, and their opponents making the leftover the remaining choice.

In subsequent games, the winners of the previous game serve first. Matches are best out of three: a player or pair must win two games (of 21 points each) to win the match. For the first rally of any doubles game, the serving pair may decide who serves and the receiving pair may decide who receives. The players change ends at the start of the second game; if the match reaches a third game, they change ends both at the start of the game and when the leading player's or pair's score reaches 11 points.

The server and receiver must remain within their service courts, without touching the boundary lines, until the server strikes the shuttlecock. The other two players may stand wherever they wish, so long as they do not block the vision of the server or receiver.

Lets

If a let is called, the rally is stopped and replayed with no change to the score. Lets may occur because of some unexpected disturbance such as a shuttlecock landing on court (having been hit there by players playing in adjacent court) or in small halls the shuttle may touch an overhead rail which can be classed as a let.

If the receiver is not ready when the service is delivered, a let shall be called; yet, if the receiver attempts to return the shuttlecock, the receiver shall be judged to have been ready.

Equipment

Badminton rules restrict the design and size of racquets and shuttlecocks.

Racquets

Badminton racquets are lightweight, with top quality racquets weighing between 70 and not including grip or strings.  They are composed of many different materials ranging from carbon fibre composite (graphite reinforced plastic) to solid steel, which may be augmented by a variety of materials. Carbon fibre has an excellent strength to weight ratio, is stiff, and gives excellent kinetic energy transfer. Before the adoption of carbon fibre composite, racquets were made of light metals such as aluminum. Earlier still, racquets were made of wood. Cheap racquets are still often made of metals such as steel, but wooden racquets are no longer manufactured for the ordinary market, because of their excessive mass and cost. Nowadays, nanomaterials such as fullerene and carbon nanotubes are added to racquets giving them greater durability.

There is a wide variety of racquet designs, although the laws limit the racquet size and shape. Different racquets have playing characteristics that appeal to different players. The traditional oval head shape is still available, but an isometric head shape is increasingly common in new racquets.

Strings

Badminton strings are thin, high performing strings with thicknesses ranging from about 0.62 to 0.73 mm. Thicker strings are more durable, but many players prefer the feel of thinner strings. String tension is normally in the range of 80 to 160 N (18 to 36 lbf). Recreational players generally string at lower tensions than professionals, typically between 80 and 110 N (18 and 25 lbf). Professionals string between about 110 and 160 N (25 and 36 lbf). Some string manufacturers measure the thickness of their strings under tension so they are actually thicker than specified when slack. Ashaway Micropower is actually 0.7mm but Yonex BG-66 is about 0.72mm.

It is often argued that high string tensions improve control, whereas low string tensions increase power.  The arguments for this generally rely on crude mechanical reasoning, such as claiming that a lower tension string bed is more bouncy and therefore provides more power. This is in fact incorrect, for a higher string tension can cause the shuttle to slide off the racquet and hence make it harder to hit a shot accurately. An alternative view suggests that the optimum tension for power depends on the player: the faster and more accurately a player can swing their racquet, the higher the tension for maximum power. Neither view has been subjected to a rigorous mechanical analysis, nor is there clear evidence in favour of one or the other. The most effective way for a player to find a good string tension is to experiment.

Grip

The choice of grip allows a player to increase the thickness of their racquet handle and choose a comfortable surface to hold. A player may build up the handle with one or several grips before applying the final layer.

Players may choose between a variety of grip materials. The most common choices are PU synthetic grips or towelling grips. Grip choice is a matter of personal preference. Players often find that sweat becomes a problem; in this case, a drying agent may be applied to the grip or hands, sweatbands may be used, the player may choose another grip material or change his/her grip more frequently.

There are two main types of grip: replacement grips and overgrips. Replacement grips are thicker, and are often used to increase the size of the handle. Overgrips are thinner (less than 1 mm), and are often used as the final layer. Many players, however, prefer to use replacement grips as the final layer. Towelling grips are always replacement grips. Replacement grips have an adhesive backing, whereas overgrips have only a small patch of adhesive at the start of the tape and must be applied under tension; overgrips are more convenient for players who change grips frequently, because they may be removed more rapidly without damaging the underlying material.

Shuttlecock

A shuttlecock (often abbreviated to shuttle; also called a birdie) is a high-drag projectile, with an open conical shape: the cone is formed from sixteen overlapping feathers embedded into a rounded cork base. The cork is covered with thin leather or synthetic material. Synthetic shuttles are often used by recreational players to reduce their costs as feathered shuttles break easily. These nylon shuttles may be constructed with either natural cork or synthetic foam base, and a plastic skirt.

Badminton rules also provide for testing a shuttlecock for the correct speed:

Shoes

Badminton shoes are lightweight with soles of rubber or similar high-grip, non-marking materials.

Compared to running shoes, badminton shoes have little lateral support. High levels of lateral support are useful for activities where lateral motion is undesirable and unexpected. Badminton, however, requires powerful lateral movements. A highly built-up lateral support will not be able to protect the foot in badminton; instead, it will encourage catastrophic collapse at the point where the shoe's support fails, and the player's ankles are not ready for the sudden loading, which can cause sprains. For this reason, players should choose badminton shoes rather than general trainers or running shoes, because proper badminton shoes will have a very thin sole, lower a person's centre of gravity, and therefore result in fewer injuries. Players should also ensure that they learn safe and proper footwork, with the knee and foot in alignment on all lunges. This is more than just a safety concern: proper footwork is also critical in order to move effectively around the court.

Technique

Strokes

Badminton offers a wide variety of basic strokes, and players require a high level of skill to perform all of them effectively. All strokes can be played either forehand or backhand. A player's forehand side is the same side as their playing hand: for a right-handed player, the forehand side is their right side and the backhand side is their left side. Forehand strokes are hit with the front of the hand leading (like hitting with the palm), whereas backhand strokes are hit with the back of the hand leading (like hitting with the knuckles). Players frequently play certain strokes on the forehand side with a backhand hitting action, and vice versa.

In the forecourt and midcourt, most strokes can be played equally effectively on either the forehand or backhand side; but in the rear court, players will attempt to play as many strokes as possible on their forehands, often preferring to play a round-the-head forehand overhead (a forehand "on the backhand side") rather than attempt a backhand overhead. Playing a backhand overhead has two main disadvantages. First, the player must turn their back to their opponents, restricting their view of them and the court. Second, backhand overheads cannot be hit with as much power as forehands: the hitting action is limited by the shoulder joint, which permits a much greater range of movement for a forehand overhead than for a backhand. The backhand clear is considered by most players and coaches to be the most difficult basic stroke in the game, since precise technique is needed in order to muster enough power for the shuttlecock to travel the full length of the court. For the same reason, backhand smashes tend to be weak.

Position of the shuttlecock and receiving player

The choice of stroke depends on how near the shuttlecock is to the net, whether it is above net height, and where an opponent is currently positioned: players have much better attacking options if they can reach the shuttlecock well above net height, especially if it is also close to the net. In the forecourt, a high shuttlecock will be met with a net kill, hitting it steeply downwards and attempting to win the rally immediately. This is why it is best to drop the shuttlecock just over the net in this situation. In the midcourt, a high shuttlecock will usually be met with a powerful smash, also hitting downwards and hoping for an outright winner or a weak reply. Athletic jump smashes, where players jump upwards for a steeper smash angle, are a common and spectacular element of elite men's doubles play. In the rearcourt, players strive to hit the shuttlecock while it is still above them, rather than allowing it to drop lower. This overhead hitting allows them to play smashes, clears (hitting the shuttlecock high and to the back of the opponents' court), and drop shots (hitting the shuttlecock softly so that it falls sharply downwards into the opponents' forecourt). If the shuttlecock has dropped lower, then a smash is impossible and a full-length, high clear is difficult.

Vertical position of the shuttlecock

When the shuttlecock is well below net height, players have no choice but to hit upwards. Lifts, where the shuttlecock is hit upwards to the back of the opponents' court, can be played from all parts of the court. If a player does not lift, his only remaining option is to push the shuttlecock softly back to the net: in the forecourt this is called a netshot; in the midcourt or rearcourt, it is often called a push or block.

When the shuttlecock is near to net height, players can hit drives, which travel flat and rapidly over the net into the opponents' rear midcourt and rearcourt. Pushes may also be hit flatter, placing the shuttlecock into the front midcourt. Drives and pushes may be played from the midcourt or forecourt, and are most often used in doubles: they are an attempt to regain the attack, rather than choosing to lift the shuttlecock and defend against smashes. After a successful drive or push, the opponents will often be forced to lift the shuttlecock.

Spin

Balls may be spun to alter their bounce (for example, topspin and backspin in tennis) or trajectory, and players may slice the ball (strike it with an angled racquet face) to produce such spin; but, since the shuttlecock is not allowed to bounce, this does not apply to badminton.

Slicing the shuttlecock so that it spins, however, does have applications, and some are particular to badminton. (See Basic strokes for an explanation of technical terms.)
* Slicing the shuttlecock from the side may cause it to travel in a different direction from the direction suggested by the player's racquet or body movement. This is used to deceive opponents.
* Slicing the shuttlecock from the side may cause it to follow a slightly curved path (as seen from above), and the deceleration imparted by the spin causes sliced strokes to slow down more suddenly towards the end of their flight path. This can be used to create dropshots and smashes that dip more steeply after they pass the net.
* When playing a netshot, slicing underneath the shuttlecock may cause it to turn over itself (tumble) several times as it passes the net. This is called a spinning netshot or tumbling netshot. The opponent will be unwilling to address the shuttlecock until it has corrected its orientation.

Due to the way that its feathers overlap, a shuttlecock also has a slight natural spin about its axis of rotational symmetry. The spin is in a counter-clockwise direction as seen from above when dropping a shuttlecock. This natural spin affects certain strokes: a tumbling netshot is more effective if the slicing action is from right to left, rather than from left to right. 

Biomechanics

Badminton biomechanics have not been the subject of extensive scientific study, but some studies confirm the minor role of the wrist in power generation and indicate that the major contributions to power come from internal and external rotations of the upper and lower arm. Recent guides to the sport thus emphasize forearm rotation rather than wrist movements. 

The feathers impart substantial drag, causing the shuttlecock to decelerate greatly over distance. The shuttlecock is also extremely aerodynamically stable: regardless of initial orientation, it will turn to fly cork-first, and remain in the cork-first orientation.

One consequence of the shuttlecock's drag is that it requires considerable power to hit it the full length of the court, which is not the case for most racquet sports. The drag also influences the flight path of a lifted (lobbed) shuttlecock: the parabola of its flight is heavily skewed so that it falls at a steeper angle than it rises. With very high serves, the shuttlecock may even fall vertically.

Other factors

When defending against a smash, players have three basic options: lift, block, or drive. In singles, a block to the net is the most common reply. In doubles, a lift is the safest option but it usually allows the opponents to continue smashing; blocks and drives are counter-attacking strokes, but may be intercepted by the smasher's partner. Many players use a backhand hitting action for returning smashes on both the forehand and backhand sides, because backhands are more effective than forehands at covering smashes directed to the body. Hard shots directed towards the body are difficult to defend.

The service is restricted by the Laws and presents its own array of stroke choices. Unlike in tennis, the server's racquet must be pointing in a downward direction to deliver the serve so normally the shuttle must be hit upwards to pass over the net. The server can choose a low serve into the forecourt (like a push), or a lift to the back of the service court, or a flat drive serve. Lifted serves may be either high serves, where the shuttlecock is lifted so high that it falls almost vertically at the back of the court, or flick serves, where the shuttlecock is lifted to a lesser height but falls sooner.

Deception

Once players have mastered these basic strokes, they can hit the shuttlecock from and to any part of the court, powerfully and softly as required. Beyond the basics, however, badminton offers rich potential for advanced stroke skills that provide a competitive advantage. Because badminton players have to cover a short distance as quickly as possible, the purpose of many advanced strokes is to deceive the opponent, so that either he is tricked into believing that a different stroke is being played, or he is forced to delay his movement until he actually sees the shuttle's direction. "Deception" in badminton is often used in both of these senses. When a player is genuinely deceived, he will often lose the point immediately because he cannot change his direction quickly enough to reach the shuttlecock. Experienced players will be aware of the trick and cautious not to move too early, but the attempted deception is still useful because it forces the opponent to delay his movement slightly. Against weaker players whose intended strokes are obvious, an experienced player may move before the shuttlecock has been hit, anticipating the stroke to gain an advantage.

Slicing and using a shortened hitting action are the two main technical devices that facilitate deception. Slicing involves hitting the shuttlecock with an angled racquet face, causing it to travel in a different direction than suggested by the body or arm movement. Slicing also causes the shuttlecock to travel more slowly than the arm movement suggests. For example, a good crosscourt sliced dropshot will use a hitting action that suggests a straight clear or smash, deceiving the opponent about both the power and direction of the shuttlecock. A more sophisticated slicing action involves brushing the strings around the shuttlecock during the hit, in order to make the shuttlecock spin. This can be used to improve the shuttle's trajectory, by making it dip more rapidly as it passes the net; for example, a sliced low serve can travel slightly faster than a normal low serve, yet land on the same spot. Spinning the shuttlecock is also used to create spinning netshots (also called tumbling netshots), in which the shuttlecock turns over itself several times (tumbles) before stabilizing; sometimes the shuttlecock remains inverted instead of tumbling. The main advantage of a spinning netshot is that the opponent will be unwilling to address the shuttlecock until it has stopped tumbling, since hitting the feathers will result in an unpredictable stroke. Spinning netshots are especially important for high level singles players.

The lightness of modern racquets allows players to use a very short hitting action for many strokes, thereby maintaining the option to hit a powerful or a soft stroke until the last possible moment. For example, a singles player may hold his racquet ready for a netshot, but then flick the shuttlecock to the back instead with a shallow lift when she or he notices the opponent has moved before the actual shot was played. A shallow lift takes less time to reach the ground and as mentioned above a rally is over when the shuttlecock touches the ground. This makes the opponent's task of covering the whole court much more difficult than if the lift was hit higher and with a bigger, obvious swing. A short hitting action is not only useful for deception: it also allows the player to hit powerful strokes when he has no time for a big arm swing. A big arm swing is also usually not advised in badminton because bigger swings make it more difficult to recover for the next shot in fast exchanges. The use of grip tightening is crucial to these techniques, and is often described as finger power. Elite players develop finger power to the extent that they can hit some power strokes, such as net kills, with less than a 10 cm racquet swing.

It is also possible to reverse this style of deception, by suggesting a powerful stroke before slowing down the hitting action to play a soft stroke. In general, this latter style of deception is more common in the rearcourt (for example, dropshots disguised as smashes), whereas the former style is more common in the forecourt and midcourt (for example, lifts disguised as netshots).

Deception is not limited to slicing and short hitting actions. Players may also use double motion, where they make an initial racquet movement in one direction before withdrawing the racquet to hit in another direction. Players will often do this to send opponents in the wrong direction. The racquet movement is typically used to suggest a straight angle but then play the stroke cross court, or vice versa. Triple motion is also possible, but this is very rare in actual play. An alternative to double motion is to use a racquet head fake, where the initial motion is continued but the racquet is turned during the hit. This produces a smaller change in direction, but does not require as much time.

Strategy

To win in badminton, players need to employ a wide variety of strokes in the right situations. These range from powerful jumping smashes to delicate tumbling net returns. Often rallies finish with a smash, but setting up the smash requires subtler strokes. For example, a netshot can force the opponent to lift the shuttlecock, which gives an opportunity to smash. If the netshot is tight and tumbling, then the opponent's lift will not reach the back of the court, which makes the subsequent smash much harder to return.

Deception is also important. Expert players prepare for many different strokes that look identical, and use slicing to deceive their opponents about the speed or direction of the stroke. If an opponent tries to anticipate the stroke, he may move in the wrong direction and may be unable to change his body momentum in time to reach the shuttlecock.

Singles

Since one person needs to cover the entire court, singles tactics are based on forcing the opponent to move as much as possible; this means that singles strokes are normally directed to the corners of the court. Players exploit the length of the court by combining lifts and clears with drop shots and net shots. Smashing tends to be less prominent in singles than in doubles because the smasher has no partner to follow up his effort and is thus vulnerable to a skillfully placed return. Moreover, frequent smashing can be exhausting in singles where the conservation of a player's energy is at a premium. However, players with strong smashes will sometimes use the shot to create openings, and players commonly smash weak returns to try to end rallies.

In singles, players will often start the rally with a forehand high serve or with a flick serve. Low serves are also used frequently, either forehand or backhand. Drive serves are rare.

At high levels of play, singles demands extraordinary fitness. Singles is a game of patient positional manoeuvring, unlike the all-out aggression of doubles.

Doubles

Both pairs will try to gain and maintain the attack, smashing downwards when the opportunity arises. Whenever possible, a pair will adopt an ideal attacking formation with one player hitting down from the rearcourt, and his partner in the midcourt intercepting all smash returns except the lift. If the rearcourt attacker plays a dropshot, his partner will move into the forecourt to threaten the net reply. If a pair cannot hit downwards, they will use flat strokes in an attempt to gain the attack. If a pair is forced to lift or clear the shuttlecock, then they must defend: they will adopt a side-by-side position in the rear midcourt, to cover the full width of their court against the opponents' smashes. In doubles, players generally smash to the middle ground between two players in order to take advantage of confusion and clashes.

At high levels of play, the backhand serve has become popular to the extent that forehand serves have become fairly rare at a high level of play. The straight low serve is used most frequently, in an attempt to prevent the opponents gaining the attack immediately. Flick serves are used to prevent the opponent from anticipating the low serve and attacking it decisively.

At high levels of play, doubles rallies are extremely fast. Men's doubles is the most aggressive form of badminton, with a high proportion of powerful jump smashes and very quick reflex exchanges. Because of this, spectator interest is sometimes greater for men's doubles than for singles.

Mixed Doubles

In mixed doubles, both pairs typically try to maintain an attacking formation with the woman at the front and the man at the back. This is because the male players are usually substantially stronger, and can therefore produce smashes that are more powerful. As a result, mixed doubles require greater tactical awareness and subtler positional play. Clever opponents will try to reverse the ideal position, by forcing the woman towards the back or the man towards the front. In order to protect against this danger, mixed players must be careful and systematic in their shot selection. 

At high levels of play, the formations will generally be more flexible: the top women players are capable of playing powerfully from the back-court, and will happily do so if required. When the opportunity arises, however, the pair will switch back to the standard mixed attacking position, with the woman in front and men in the back.

Organization

Governing bodies

The Badminton World Federation (BWF) is the internationally recognized governing body of the sport responsible for conduction of tournaments and approaching fair play. Five regional confederations are associated with the BWF:

* Asia: Badminton Asia Confederation (BAC)
* Africa: Badminton Confederation of Africa (BCA)
* Americas: Badminton Pan Am (North America and South America belong to the same confederation; BPA)
* Europe: Badminton Europe (BE)
* Oceania: Badminton Oceania (BO)

Competitions

The BWF organizes several international competitions, including the Thomas Cup, the premier men's international team event first held in 1948–1949, and the Uber Cup, the women's equivalent first held in 1956–1957. The competitions now take place once every two years. More than 50 national teams compete in qualifying tournaments within continental confederations for a place in the finals. The final tournament involves 12 teams, following an increase from eight teams in 2004.

The Sudirman Cup, a gender-mixed international team event held once every two years, began in 1989. Teams are divided into seven levels based on the performance of each country. To win the tournament, a country must perform well across all five disciplines (men's doubles and singles, women's doubles and singles, and mixed doubles). Like association football (soccer), it features a promotion and relegation system in every level.

Badminton was a demonstration event in the 1972 and 1988 Summer Olympics. It became an official Summer Olympic sport at the Barcelona Olympics in 1992 and its gold medals now generally rate as the sport's most coveted prizes for individual players.

In the BWF World Championships, first held in 1977, currently only the highest ranked 64 players in the world, and a maximum of four from each country, can participate in any category. In both the Olympic and BWF World competitions restrictions on the number of participants from any one country have caused some controversy because they sometimes result in excluding elite world level players from the strongest badminton nations. The Thomas, Uber, and Sudirman Cups, the Olympics, and the BWF World (and World Junior Championships), are all categorized as level one tournaments.

At the start of 2007, the BWF  introduced a new tournament structure for the highest level tournaments aside from those in level one: the BWF Super Series. This level two tournament series, a tour for the world's elite players,  stages twelve open tournaments around the world with 32 players (half the previous limit). The players collect points that determine whether they can play in Super Series Finals held at the year end. Among the tournaments in this series is the venerable All-England Championships, first held in 1900, which was once considered the unofficial world championships of the sport. 

Level three tournaments consist of Grand Prix Gold and Grand Prix event. Top players can collect the world ranking points and enable them to play in the BWF Super Series open tournaments. These include the regional competitions in Asia (Badminton Asia Championships) and Europe (European Badminton Championships), which produce the world's best players as well as the Pan America Badminton Championships.

The level four tournaments, known as International Challenge, International Series, and Future Series, encourage participation by junior players. 

Comparison with tennis

Badminton is frequently compared to tennis. The following is a list of manifest differences:
* Scoring: In badminton, a match is played best 2 of 3 games, with each game played up to 21 points. In tennis a match is played best of 3 or 5 sets, each set consisting of 6 games and each game ends when one player wins 4 points or wins two consecutive points at deuce points.  If both team are tied at "game point", they must play until one team achieves a two-point advantage.  However, at 29all, whoever scores the golden point will win. In tennis, if the score is tied 66 in a set, a tiebreaker will be played, which ends once a player reaches 7 points or when one player has a two-point advantage.
* In tennis, the ball may bounce once before the point ends; in badminton, the rally ends once the shuttlecock touches the floor.
* In tennis, the serve is dominant to the extent that the server is expected to win most of his service games (at advanced level & onwards); a break of service, where the server loses the game, is of major importance in a match. In badminton a server has far less an advantage, and is unlikely to score an ace (unreturnable serve).
* In tennis, the server has two chances to hit a serve into the service box; in badminton, the server is allowed only one attempt.
* A tennis court is approximately twice the length and width of a badminton court.
* Tennis racquets are about four times as heavy as badminton racquets, 10 to versus 2 to.   Tennis balls are more than eleven times heavier than shuttlecocks, 57 g versus 5 g.  
* The fastest recorded tennis stroke is Samuel Groth's  serve,  whereas the fastest badminton stroke during gameplay was Fu Haifeng's 206 mi/h recorded smash.

Statistics such as the smash speed, above, prompt badminton enthusiasts to make other comparisons that are more contentious. For example, it is often claimed that badminton is the fastest racquet sport. Although badminton holds the record for the fastest initial speed of a racquet sports projectile, the shuttlecock decelerates substantially faster than other projectiles such as tennis balls. In turn, this qualification must be qualified by consideration of the distance over which the shuttlecock travels: a smashed shuttlecock travels a shorter distance than a tennis ball during a serve.

While fans of badminton and tennis often claim that their sport is the more physically demanding, such comparisons are difficult to make objectively because of the differing demands of the games. No formal study currently exists evaluating the physical condition of the players or demands during game play.

Badminton and tennis techniques differ substantially. The lightness of the shuttlecock and of badminton racquets allow badminton players to make use of the wrist and fingers much more than tennis players; in tennis the wrist is normally held stable, and playing with a mobile wrist may lead to injury. For the same reasons, badminton players can generate power from a short racquet swing: for some strokes such as net kills, an elite player's swing may be less than 5 cm. For strokes that require more power, a longer swing will typically be used, but the badminton racquet swing will rarely be as long as a typical tennis swing. A shuttlecock  (also called a bird or birdie) is a high-drag projectile used in the sport of badminton. It has an open conical shape: the cone is formed from 16 or so overlapping feathers, usually goose or duck, embedded into a rounded cork base. The cork is covered with thin leather.  The shuttlecock's shape makes it extremely aerodynamically stable.  Regardless of initial orientation, it will turn to fly cork first, and remain in the cork-first orientation. The name shuttlecock is frequently shortened to shuttle. The "shuttle" part of the name was probably derived from its back-and-forth motion during the game, resembling the shuttle of a loom; the "cock" part of the name was probably derived from the resemblance of the feathers to those on a cockerel.

Feathered vs. synthetic shuttlecocks

The feathers are brittle; shuttlecocks break easily and often need to be replaced several times during a game. For this reason, synthetic shuttlecocks have been developed that replace the feathers with a plastic skirt. Players often refer to synthetic shuttlecocks as plastics and feathered shuttlecocks as feathers. 

Feather Shuttles need to be properly humidified for at least 4 hours prior to play in order to fly the correct distance at the proper speed and to last longer.  Correctly humidified feathers flex during play enhancing the shuttle's change-in-speed and durability.  Dry feathers are brittle and break easily causing the shuttle to wobble. Saturated feathers are 'mushy', making the feather cone narrow too much when strongly hit, which causes the shuttle to fly overly far and fast.  Humidification boxes are often used, but a simple moist sponge inserted in the feather end of the closed shuttle tube will work quite nicely.  Water should never touch the cork of the shuttle. Shuttles are tested prior to play to make sure they fly true and at the proper speed and distance.  Different weights of shuttles are used to compensate for local atmospheric conditions.  Both humidity and height above sea level affect shuttle flight.  A proper shuttle will generally travel from the back line of the court to just short of the long doubles service line on the opposite side of the net, with a full underhand hit from an average player.  

The cost of good quality feathers is similar to that of good quality plastics, but plastics are far more durable, typically lasting many matches without any impairment to their flight. 

Most experienced and skillful players greatly prefer feathers, and serious tournaments or leagues are always played using feather shuttlecocks of the highest quality.  Experienced players generally prefer the "feel" of feathered shuttlecocks and assert that they are able to control the flight of feathers better than of plastics. In Asia, where feather shuttlecocks are more affordable than in Europe and North America, plastic shuttlecocks are hardly used at all.

The playing characteristics of plastics and feathers are substantially different. Plastics fly more slowly on initial impact, but slow down less towards the end of their flight. While feathers tend to drop straight down on a clear shot, plastics never quite return to a straight drop, falling more on a diagonal. Feather shuttles may come off the strings at speeds in excess of 320 km/h (200 mph) but slow down faster as they drop. For this reason, the feather shuttle makes the game seem faster, but also allows more time to play strokes. Because feather shuttles fly more quickly off the racquet face they also tend to cause less shoulder impact and injury.

Specifications

A shuttlecock weighs around . It has 16 feathers with each feather 70 mm in length. The diameter of the cork is 25 to and the diameter of the circle that the feathers make is around 54 mm.
sixteen 16
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16
 How many feathers, traditionally formed the cone of a badminton shetland coat. 

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