Oligodynamic effect - wikipedia Oligodynamic effect Jump to : navigation , search Silver spoons self - sanitize due to the oligodynamic effect The oligodynamic effect ( from Greek oligos `` few '' , and dynamis `` force '' ) is a biocidal effect of metals , especially heavy metals , that occurs even in low concentrations . The effect was discovered by Karl Wilhelm von Nägeli , although he did not identify the cause . Brass doorknobs and silverware both exhibit this effect to an extent . Contents ( hide ) 1 Mechanism 2 Use 2.1 Aluminium 2.2 Antimony 2.3 Arsenic 2.4 Barium 2.5 Bismuth 2.6 Boron 2.7 Copper 2.8 Gold 2.9 Lead 2.10 Mercury 2.11 Nickel 2.12 Silver 2.13 Thallium 2.14 Tin 2.15 Zinc 3 Safety 4 See also 5 References Mechanism ( edit ) The metals react with thiol ( - SH ) or amine ( - NH ) groups of proteins , a mode of action to which microorganisms may develop resistance . Such resistance may be transmitted by plasmids . Use ( edit ) Aluminium ( edit ) Aluminium acetate ( Burow 's solution ) is used as an astringent mild antiseptic . Aluminium - based antiperspirant ingredients ( `` aluminium salts '' ) such as aluminium chlorohydrate , activated aluminium chlorohydrates , and aluminium - zirconium - glycine ( AZG ) complexes work by forming superficial plugs in the sweat ducts , reducing the flow of perspiration . Antimony ( edit ) Orthoesters of diarylstibinic acids are fungicides and bactericides , used in paints , plastics , and fibers . Trivalent organic antimony was used in therapy for schistosomiasis . Arsenic ( edit ) For many decades , arsenic was used medicinally to treat syphilis . It is still used in sheep dips , rat poisons , wood preservatives , weed killers , and other pesticides . Arsenic is also still used for murder by poisoning , for which use it has a long and continuing history in both literature and fact . Barium ( edit ) Barium polysulfide is a fungicide and acaricide used in fruit and grape growing . Bismuth ( edit ) Bismuth compounds have been used because of their astringent , antiphlogistic , bacteriostatic , and disinfecting actions . In dermatology bismuth subgallate is still used in vulnerary salves and powders as well as in antimycotics . In the past , bismuth has also been used to treat syphilis and malaria . Boron ( edit ) Boric acid esters derived from glycols ( example , organo - borate formulation , Biobor JF ) are being used for the control of microorganisms in fuel systems containing water . Copper ( edit ) Brass vessels release a small amount of copper ions into stored water , thus killing fecal bacterial counts as high as 1 million bacteria per milliliter . Copper sulfate mixed with lime is used as a fungicide and antihelminthic . Copper sulfate is used chiefly to destroy green algae ( algicide ) that grow in reservoirs , stock ponds , swimming pools , and fish tanks . Copper 8 - hydroxyquinoline is sometimes included in paint to prevent mildew . Paint containing copper is used on boat bottoms to prevent barnacle growth Gold ( edit ) Gold is used in dental inlays and inhibits the growth of bacteria . Lead ( edit ) Physicians prescribed various forms of lead to heal ailments ranging from constipation to infectious diseases such as the plague . Lead was also used to preserve or sweeten wine . Lead arsenate is used in insecticides and herbicides . Some organic lead compounds are used as industrial biocides : thiomethyl triphenyllead is used as an antifungal agent , cotton preservative , and lubricant additive ; thiopropyl triphenyllead as a rodent repellant ; tributyllead acetate as a wood and cotton preservative ; tributyllead imidazole as a lubricant additive and cotton preservative . Mercury ( edit ) Phenylmercuric borate and acetate were used for disinfecting mucous membranes at an effective concentration of 0.07 % in aqueous solutions . Due to toxicological and ecotoxicological reasons phenylmercury salts are no longer in use . However , some surgeons use mercurochrome despite toxicological objections . Dental amalgam used in fillings inhibits bacterial reproduction . Organic mercury compounds have been used as topical disinfectants ( thimerosal , nitromersol and merbromin ) and preservatives in medical preparations ( thimerosal ) and grain products ( both methyl and ethyl mercurials ) . Mercury was used in the treatment of syphilis . Calomel was commonly used in infant teething powders in the 1930s and 1940s . Mercurials are also used agriculturally as insecticides and fungicides . Nickel ( edit ) The toxicity of nickel to bacteria , yeasts , and fungi differs considerably . Silver ( edit ) The metabolism of bacteria is adversely affected by silver ions at concentrations of 0.01 -- 0.1 mg / L. Therefore , even less soluble silver compounds , such as silver chloride , also act as bactericides or germicides , but not the much less soluble silver sulfide . In the presence of atmospheric oxygen , metallic silver also has a bactericidal effect due to the formation of silver oxide , which is soluble enough to cause it . Bactericidal concentrations are reduced rapidly by adding colloidal silver , which has a high surface area . Even objects with a solid silver surface ( e.g. , table silver , silver coins , or silver foil ) have a bactericidal effect . Silver drinking vessels were carried by military commanders on expeditions for protection against disease . It was once common to place silver foil or even silver coins on wounds for the same reason . Silver sulfadiazine is used as an antiseptic ointment for extensive burns . An equilibrium dispersion of colloidal silver with dissolved silver ions can be used to purify drinking water at sea . Silver is incorporated into medical implants and devices such as catheters . Surfacine ( silver iodide ) is a relatively new antimicrobial for application to surfaces . Silver - impregnated wound dressings have proven especially useful against antibiotic - resistant bacteria . Silver nitrate is used as a hemostatic , antiseptic and astringent . At one time , many states required that the eyes of newborns be treated with a few drops of silver nitrate to guard against an infection of the eyes called gonorrheal neonatal ophthalmia , which the infants might have contracted as they passed through the birth canal . Silver ions are increasingly incorporated into many hard surfaces , such as plastics and steel , as a way to control microbial growth on items such as toilet seats , stethoscopes , and even refrigerator doors . Among the newer products being sold are plastic food containers infused with silver nanoparticies , which are intended to keep food fresher , and silver - infused athletic shirts and socks , which claim to minimize odors . Thallium ( edit ) Thallium compounds such as thallium sulfate have been used for impregnating wood and leather to kill fungal spores and bacteria , and for the protection of textiles from attack by moths . Thallium sulfate has been used as a depilatory and in the treatment of venereal disease , skin fungal infections , and tuberculosis . Tin ( edit ) Tetrabutyltin is used as an antifouling paint for ships , for the prevention of slimes in industrial recirculating water systems , for combating freshwater snails that cause bilharzia , as a wood and textile preservative , and as a disinfectant . Tricyclohexyltin hydroxide is used as an acaricide . Triphenyltin hydroxide and triphenyltin acetate are used as fungicides . Zinc ( edit ) Zinc oxide is used as a weak antiseptic ( and sunscreen ) , and in paints as a white pigment and mold - growth inhibitor . Zinc chloride is a common ingredient in mouthwashes and deodorants , and zinc pyrithione is an ingredient in antidandruff shampoos . Galvanized ( zinc - coated ) fittings on roofs impede the growth of algae . Copper - and zinc - treated shingles are available . Zinc iodide and zinc sulfate are used as topical antiseptics . Safety ( edit ) Besides the individual toxic effects of each metal , a wide range of metals are nephrotoxic in humans and / or in animals . Some metals and their compounds are carcinogenic to humans . A few metals , such as lead and mercury , can cross the placental barrier and impact fetal development . Several ( cadmium , zinc , copper , and mercury ) can induce special protein complexes called metallothioneins . See also ( edit ) Medical uses of silver Antimicrobial properties of copper References ( edit ) Jump up ^ Nägeli , Karl Wilhelm ( 1893 ) , `` Über oligodynamische Erscheinungen in lebenden Zellen '' , Neue Denkschriften der allgemeinen Schweizerischen Gesellschaft für die gesamte Naturwissenschaft , XXXIII ( 1 ) ^ Jump up to : Harke , Hans - P. ( 2007 ) , `` Disinfectants '' , Ullmann 's Encyclopedia of Industrial Chemistry ( 7th ed . ) , Wiley , pp. 1 -- 17 , doi : 10.1002 / 14356007. a08_551 Jump up ^ Berth - Jones , John ( 2010 ) , `` Topical Therapy '' , in Burns , Tony ; Breathnach , Stephen ; Cox , Neil ; Griffiths , Christopher , Rook 's Textbook of Dermatology , 4 ( 8th ed . ) , Wiley - Blackwell , p . 73.16 , ISBN 978 - 1 - 4051 - 6169 - 5 Jump up ^ Cai , Zhengwei ; Hakkinen , Pertti J. ( 2005 ) , `` Deodorants and Antiperspirants '' , in Wexler , Philip , Encyclopedia of Toxicology , 1 ( 2nd ed . ) , Elsevier , pp. 737 -- 738 , ISBN 0 - 12 - 745354 - 7 Jump up ^ Grund , Sabina C. ; Hanusch , Kunibert ; Breunig , Hans J. ; Wolf , Hans Uwe ( 2007 ) , `` Antimony and Antimony Compounds '' , Ullmann 's Encyclopedia of Industrial Chemistry ( 7th ed . ) , Wiley , pp. 1 -- 34 , doi : 10.1002 / 14356007. a03_055. pub2 Jump up ^ Leikin , Jerrold B. ; Paloucek , Frank P. , eds. ( 2008 ) , `` Antimony '' , Poisoning and Toxicology Handbook ( 4th ed . ) , Informa , p. 753 , ISBN 978 - 1 - 4200 - 4479 - 9 Jump up ^ Kapp , Robert ( 2005 ) , `` Arsenic '' , Encyclopedia of Toxicology , 1 ( 2nd ed . ) , Elsevier , pp. 168 -- 171 , ISBN 0 - 12 - 745354 - 7 Jump up ^ Kresse , Robert ; Baudis , Ulrich ; Jäger , Paul ; Riechers , H. Hermann ; Wagner , Heinz ; Winkler , Jochen ; Wolf , Hans Uwe ( 2007 ) , `` Barium and Barium Compounds '' , Ullmann 's Encyclopedia of Industrial Chemistry ( 7th ed . ) , Wiley , pp. 1 -- 21 , doi : 10.1002 / 14356007. a03_325. pub2 Jump up ^ Krüger , Joachim ; Winkler , Peter ; Lüderitz , Eberhard ; Lück , Manfred ; Wolf , Hans Uwe ( 2007 ) , `` Bismuth , Bismuth Alloys , and Bismuth Compounds '' , Ullmann 's Encyclopedia of Industrial Chemistry ( 7th ed . ) , Wiley , pp. 1 -- 22 , doi : 10.1002 / 14356007. a04_171 Jump up ^ Gad , Shayne C. ; Mehendale , Harihara M. ( 2005 ) , `` Bismuth '' , Encyclopedia of Toxicology , 1 ( 2nd ed . ) , Elsevier , pp. 312 -- 314 , ISBN 0 - 12 - 745354 - 7 Jump up ^ Brotherton , Robert J. ; Weber , C. Joseph ; Guibert , Clarence R. ; Little , John L. ( 2007 ) , `` Boron Compounds '' , Ullmann 's Encyclopedia of Industrial Chemistry ( 7th ed . ) , Wiley , pp. 1 -- 23 , doi : 10.1002 / 14356007. a04_309 ^ Jump up to : Bauman , Robert W. ( 2012 ) , Microbiology with diseases by body system ( 3rd ed . ) , Benjamin Cummings , pp. 278 -- 279 , ISBN 978 - 0 - 321 - 71271 - 4 Jump up ^ Gad , Shayne C. ( 2005 ) , `` Copper '' , Encyclopedia of Toxicology , 1 ( 2nd ed . ) , Elsevier , pp. 665 -- 667 , ISBN 0 - 12 - 745354 - 7 ^ Jump up to : Tortora , Gerard J. ; Funke , Berdell R. ; Case , Christine L. ( 2010 ) , Microbiology : An Introduction ( 10th ed . ) , Benjamin Cummings , pp. 300 -- 301 , ISBN 978 - 0 - 321 - 55007 - 1 ^ Jump up to : Cowan , Marjorie Kelly ( 2012 ) , Microbiology : A Systems Approach ( 3rd ed . ) , pp. 320 -- 321 , ISBN 978 - 0 - 07 - 352252 - 4 Jump up ^ Sutherland , Charles A. ; Milner , Edward F. ; Kerby , Robert C. ; Teindl , Herbert ; Melin , Albert ; Bolt , Hermann M. ( 2007 ) , `` Lead '' , Ullmann 's Encyclopedia of Industrial Chemistry ( 7th ed . ) , Wiley , doi : 10.1002 / 14356007. a15_193. pub2 Jump up ^ Gad , Shayne C. ( 2005 ) , `` Lead '' , in Wexler , Philip , Encyclopedia of Toxicology , 2 ( 2nd ed . ) , Elsevier , pp. 705 -- 709 , ISBN 0 - 12 - 745354 - 7 Jump up ^ Carr , Dodd S. ( 2007 ) , `` Lead Compounds '' , Ullmann 's Encyclopedia of Industrial Chemistry ( 7th ed . ) , Wiley , pp. 1 -- 10 , doi : 10.1002 / 14356007. a15_249 Jump up ^ Gad , Shayne C. ( 2005 ) , `` Mercury '' , Encyclopedia of Toxicology , 3 ( 2nd ed . ) , Elsevier , pp. 36 -- 39 , ISBN 0 - 12 - 745354 - 7 Jump up ^ Lascelles , Keith ; Morgan , Lindsay G. ; Nicholls , David ; Beyersmann , Detmar ( 2007 ) , `` Nickel Compounds '' , Ullmann 's Encyclopedia of Industrial Chemistry ( 7th ed . ) , Wiley , pp. 1 -- 16 , doi : 10.1002 / 14356007. a17_235. pub2 Jump up ^ Renner , Hermann ; Schlamp , Günther ; Zimmermann , Klaus ; Weise , Wolfgang ; Tews , Peter ; Dermann , Klaus ; Knödler , Alfons ; Schröder , Karl - Heinz ; Kempf , Bernd ; Lüschow , Hans Martin ; Drieselmann , Ralf ; Peter , Catrin ; Schiele , Rainer ( 2007 ) , `` Silver , Silver Compounds , and Silver Alloys '' , Ullmann 's Encyclopedia of Industrial Chemistry ( 7th ed . ) , Wiley , pp. 1 -- 17 , doi : 10.1002 / 14356007. a24_107 Jump up ^ Micke , Heinrich ; Wolf , Hans Uwe ( 2007 ) , `` Thallium and Thallium Compounds '' , Ullmann 's Encyclopedia of Industrial Chemistry ( 7th ed . ) , Wiley , pp. 1 -- 14 , doi : 10.1002 / 14356007. a26_607 Jump up ^ Gad , Shayne C. ( 2005 ) , `` Thallium '' , Encyclopedia of Toxicology , 4 ( 2nd ed . ) , Elsevier , pp. 165 -- 166 , ISBN 0 - 12 - 745354 - 7 Jump up ^ Graf , Günter G. ( 2007 ) , `` Tin , Tin Alloys , and Tin Compounds '' , Ullmann 's Encyclopedia of Industrial Chemistry ( 7th ed . ) , Wiley , pp. 1 -- 35 , doi : 10.1002 / 14356007. a27_049 Jump up ^ Leikin , Jerrold B. ; Paloucek , Frank P. , eds. ( 2008 ) , `` Zinc Oxide '' , Poisoning and Toxicology Handbook ( 4th ed . ) , Informa , p. 705 , ISBN 978 - 1 - 4200 - 4479 - 9 Jump up ^ Rohe , Dieter M.M. ; Wolf , Hans Uwe ( 2007 ) , `` Zinc Compounds '' , Ullmann 's Encyclopedia of Industrial Chemistry ( 7th ed . ) , Wiley , pp. 1 -- 6 , doi : 10.1002 / 14356007. a28_537 Jump up ^ Rankin , Gary O. ( 2005 ) , `` Kidney '' , Encyclopedia of Toxicology , 2 ( 2nd ed . ) , Elsevier , pp. 666 -- 689 , ISBN 0 - 12 - 745354 - 7 Jump up ^ Gad , Shayne C. ( 2005 ) , `` Metals '' , in Wexler , Philip , Encyclopedia of Toxicology , 3 ( 2nd ed . ) , Elsevier , p. 49 , ISBN 0 - 12 - 745354 - 7 Retrieved from `` https://en.wikipedia.org/w/index.php?title=Oligodynamic_effect&oldid=806142199 '' Categories : Biology and pharmacology of chemical elements Biocides Hidden categories : All articles with unsourced statements Articles with unsourced statements from August 2017 Use dmy dates from January 2013 Talk Contents About Wikipedia Български Deutsch Français Magyar Русский Українська Edit links This page was last edited on 20 October 2017 , at 00 : 04 . Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply . By using this site , you agree to the Terms of Use and Privacy Policy . Wikipedia ® is a registered trademark of the Wikimedia Foundation , Inc. , a non-profit organization . About Wikipedia

Question: the oligodynamic effect is a phenomenon that describes

a biocidal effect of metals, especially heavy metals, that occurs even in low concentrations


Bridge scoring - wikipedia Bridge scoring Jump to : navigation , search See also : Glossary of contract bridge terms Bridge scoring is keeping score in contract bridge . There are two main categories of scoring : duplicate and rubber scoring . While based upon the same basic elements of scoring , they differ in how the elements are applied to individual deals and in how these are then totaled . Chicago , being a variant of rubber bridge , uses an adaptation of rubber bridge scoring . Duplicate bridge has many variations for scoring , comparing and ranking the relative performance of partnerships and teams playing the same deals as their competitors . Contents ( hide ) 1 Terminology 2 Scoring elements 2.1 Contract points 2.2 Overtrick points 2.3 Slam bonus 2.4 Doubled or redoubled bonus 2.5 Penalty points 2.6 Rubber bonus 2.7 Honor bonus or honors 2.8 Game or part - game bonus 3 Rubber bridge 3.1 The score sheet 3.2 An example rubber 4 Duplicate bridge 4.1 Scoring deals 4.1. 1 Example results for a sixteen board match 4.2 Comparing deals 4.2. 1 Matchpoint scoring 4.2. 2 International Match Point scoring 5 History of Contract bridge scoring 5.1 Scoring of tricks in no trump contracts 5.2 Scoring of undertricks 5.3 8 - Level bids 5.4 International Match Points 6 References 7 External links Terminology ( edit ) The following terms and concepts , defined in the glossary of contract bridge terms , are essential to understanding bridge scoring : Contract Denomination Down Honors Make or Made Odd tricks Overtrick Slam and grand slam Undertricks Undoubled , doubled and redoubled vulnerable , not vulnerable and none vulnerable Scoring elements ( edit ) Bridge scoring consists of nine elements . Not all elements are included in all game variants and the method of accumulation of the elements over several deals varies . If the contract is made , the score for each such deal consists of : Contract points , assigned to each odd trick bid and made Overtrick points , assigned for each trick taken over the contracted number of odd tricks A slam bonus for a small slam or grand slam contract bid and made A bonus , colloquially known as ' for insult ' , is received at the end of any deal in which a doubled or redoubled contract is bid and made If the contract is defeated , the defenders receive Penalty points , assigned for every undertrick In rubber bridge only , A rubber bonus is received at the end of a completed rubber by the side that is first to win two games . A rubber bonus is also awarded for some game and part - game scores at the end of an unfinished rubber An honor bonus is received by any player at the end of any deal in which he held particular honor cards . In duplicate bridge only , A partial - game bonus is received at the end of each deal for any partial game contract bid and made A game bonus is received at the end of each deal for any game contract bid and made Contract points ( edit ) Contract points are awarded for each odd trick bid and made . Their values depend on the suit ( or notrump ) and whether the contract is doubled or redoubled ; they are not affected by vulnerability . Tricks won beyond that necessary to fulfill the contract are referred to as overtricks and their scoring points are accounted for separately because their values are dependent upon declarer 's vulnerability . Denomination Contract Points Per Trick Undoubled Doubled Redoubled Notrump First trick Subsequent tricks 40 30 80 60 160 120 Major suits 30 60 120 Minor suits 20 40 80 Overtrick points ( edit ) When declarer makes overtricks , their score value depends upon the contract denomination , declarer 's vulnerability and whether or not the contract is undoubled , doubled or redoubled . In an undoubled contract each overtrick earns the same as in contract points ( 30 for notrump and major suit contracts , 20 for minor suit contracts ) ; values increase significantly when the contract has been doubled or redoubled , especially when vulnerable . Contract Overtrick Points Per Trick Vulnerable Not Vulnerable Undoubled in : - Notrump - Major suit - Minor suit 30 30 20 30 30 20 Any doubled 200 100 Any redoubled 400 200 Slam bonus ( edit ) Bonuses are awarded for all slam contracts bid and made : a small slam , or successful contract to win 12 of 13 tricks , earns a bonus of 500 points if not vulnerable and 750 points if vulnerable ; a grand slam , or successful contract to win all 13 tricks , earns a bonus of 1000 points if not vulnerable and 1500 points if vulnerable . Doubled or redoubled bonus ( edit ) When a doubled or redoubled contract is made , a bonus is awarded to the declaring side . It is colloquially referred to as a bonus for `` insult '' , meaning that the opponents have insulted the pair by suggesting that the declarer will not make the contract . 50 points are awarded for a doubled contract made , and 100 points are awarded for a redoubled contract made . In scoring notation , a doubled contract is indicated by an ' X '' after the contract ( e.g. a contract of four hearts doubled is indicated by 4 ♥ X ) ; a redoubled contract is indicated by `` XX '' ( e.g. 4 ♥ XX ) . Penalty points ( edit ) When a contract is defeated , penalty points are awarded to the defending side . The value of the penalty depends on the number of undertricks , whether the declaring side is vulnerable or not vulnerable and whether the contract was undoubled , doubled or redoubled . Number of Undertricks Points Per Undertrick Vulnerable Not Vulnerable Undoubled Doubled Redoubled Undoubled Doubled Redoubled 1st undertrick 100 200 400 50 100 200 2nd and 3rd , each 300 600 200 400 4th and each subsequent 300 600 300 600 Without a double or redouble , every undertrick has a fixed cost of 100 or 50 points . The scores for ( re ) doubled undertricks are such that after the first vulnerable undertrick , n vulnerable undertricks cost the same as n + 1 undertricks when not vulnerable ; for example , four undertricks when doubled and not vulnerable cost 800 points ( 100 + 200 + 200 + 300 ) , the same as three undertricks when doubled and vulnerable ( 200 + 300 + 300 ) . Rubber bonus ( edit ) In rubber bridge only , a bonus is awarded at the conclusion of the rubber as follows : for a completed rubber , the side which wins the rubber , i.e. is first to win two games , receives a rubber bonus : if the opponents have won no games , i.e. they are not vulnerable , the rubber bonus is 700 points ; colloquially known as a ' fast rubber ' if the opponents have won one game , i.e. they are vulnerable , the rubber bonus is 500 points ; colloquially known as a ' slow rubber ' for unfinished rubbers : if but one side has won a game , it scores 300 points , and if but one side has a part - score , it scores 100 points . Honor bonus or honors ( edit ) In rubber bridge only , a bonus is awarded for any one hand holding four or five of the honors , i.e. an ace , king , queen , jack or ten . 100 points are awarded for any one hand holding any four of the five trump suit honors , and 150 points are awarded for any one hand holding all five trump suit honors , or all four aces in a notrump contract . Honors may be declared and scored at any time after the auction but for strategic reasons it is best to do so at the conclusion of play so as not to give the opponents information about the lay of the cards . Honors may be held by any of the four players , including dummy . Game or part - game bonus ( edit ) In duplicate bridge only , game and partial - game bonuses are awarded at the conclusion of each deal as follows : any partial contract , i.e. one scoring less than 100 contract points , scores a bonus of 50 points , and any game contract , i.e. one scoring 100 or more points , scores a game bonus of 300 if not vulnerable and 500 if vulnerable . Rubber bridge ( edit ) For additional scoring information for the rubber bridge variant Chicago , see Chicago scoring Rubber bridge score sheet The score sheet ( edit ) Rubber scoring is tallied on a score sheet divided into four parts where each partnership accumulates points either above the line or below the line . The objective is to win by scoring the most total points in the rubber ; the rubber is completed when one side has twice accumulated 100 or more contract points below the line . Only contract points are recorded below the line ; all other points are recorded above the line . Any of the four players may be the recorder , his side being represented in the `` We '' column and the opponents in the `` They '' column . In the ensuing examples , South is the recorder ( the ' We ' on the score sheet ) . An example rubber ( edit ) The following table summarizes the results of a rubber consisting of six deals . Deal Declarer Contract Made Down Contract Points Overtrick Points Slam Bonus ( Re ) doubled Bonus Penalty Points Honor Bonus Deal Total NS Deal Total EW 2NT ( 1 × 40 ) + ( 1 × 30 ) = 70 1 × 30 = 30 100 4 ♥ 4 × 30 = 120 120 5 ♣ 2 × 100 = 200 200 4 ♠ X 5 2 × ( 4 × 30 ) = 240 1 × 100 = 100 50 390 5 3 ♣ 3 × 20 = 60 1 × 20 = 20 80 6 6 6 6 × 20 = 120 750 150 1020 Rubber Bonus 500 Total 770 1640 The following panels illustrate the progression of the scoring on the score sheet . Deal 1 Deal 2 Deal 3 Deal 4 Deal 5 Deal 6 Rubber Bonus Total Deal 1 : South bids 2NT making 3 . Only the contract points ( 70 ) are scored below the line ; the overtrick points ( 30 ) are scored above the line . Deal 2 : West bids and makes 4 ♥ . This scores 120 contract points below the line ; since there are no overtricks , no points are scored above the line . The accumulation of 100 or more points below the line constitutes the end of the first game and is signified by the drawing of a horizontal line . Since no part - game or game bonus is awarded in rubber bridge , East - West do not receive an additional game bonus and North - South do not receive any part - game bonus . Furthermore , the part score of 70 by North - South is no longer available for accumulation towards a game by them ; the 70 points are said to be `` cut off '' as signified by the drawing of the horizontal line . Having won a game , East - West are vulnerable for all subsequent deals of the rubber meaning that they are now eligible for a larger rubber bonus if they win a second game before their opponents win one and they are susceptible to increased penalties if they are defeated in a contract . Deal 3 : West bids 5 ♣ and goes down 2 , vulnerable , undoubled . This scores 200 penalty points for North - South above the line . Deal 4 : South bids 4 ♠ doubled , not vulnerable and makes 5 . North - South score 240 contract tricks below the line , 100 overtrick points above the line and 50 points for ' insult ' above the line . Accumulating 100 or more points below the line constitutes the end of the second game , signified by the drawing of a horizontal line . Having won a game , North - South are now also vulnerable for all subsequent deals of the rubber . Deal 5 : North bids 3 ♣ and makes 4 scoring 60 contract points below the line and 20 overtrick points above the line . Deal 6 : East bids and makes 6 - a small slam holding all five top honors . This scores a game of 120 contract points and earns a slam bonus of 750 points above the line ( East - West being vulnerable ) . 150 honor points are scored above the line for holding all five honors . Having again accumulated 100 or more points below the line , East - West win a second game ; a horizontal line is drawn to end the rubber . Rubber Bonus : At the conclusion of the rubber , a rubber bonus is awarded . In this case , East - West have won a slow rubber and receive a 500 - point rubber bonus above the line . Total : The scores for each side are totalled and East - West ( the ' They ' on the score sheet ) win the rubber . Duplicate bridge ( edit ) Scoring in duplicate bridge is done in two stages : Each deal is scored as in rubber bridge but with some variations in methodology . The result of each deal by each partnership is compared to all other results for the same deal by all other partnerships . Scoring deals ( edit ) In duplicate scoring , the score for each deal is independent from all others and is a single number resulting from the addition of points awarded in accordance with either of two cases : when the contract is successful , the declaring side receives a positive score which is the sum of the following elements , if applicable : ( i ) contract points , ( ii ) overtrick points , ( iii ) a part - game or game bonus , ( iv ) a bonus for making any doubled or redoubled contract , i.e. for ' insult ' , and ( v ) a slam or grand slam bonus ; the defending side receives a negative score of the same absolute value . when the contract is defeated , the defending side receives a positive score based upon the number of tricks defeated , declarer 's vulnerability , and whether undoubled , doubled or redoubled ; the declaring side receives a negative score of the same absolute value . Example results for a sixteen board Match ( edit ) In duplicate bridge , the dealer and the status of vulnerability for each side is predetermined by the board , there being sixteen possible combinations . Board Dealer Vulnerability Declarer Contract Made Down Contract Points Overtrick Points Slam Bonus ( Re ) doubled Bonus Penalty Points Game Points Total N-S Total E-W None 1 ♥ 30 2 × 30 = 60 50 − 140 140 N-S 4 ♠ X ( 1 × 200 ) + ( 1 × 300 ) = 500 − 500 500 E-W 2 2 × 20 = 40 2 × 20 = 40 50 130 − 130 Both 1NT 40 2 × 30 = 60 50 − 150 150 5 N-S 3NT 100 − 100 100 6 E-W 3 ♥ 3 × 30 = 90 30 50 170 − 170 7 Both 3 ♣ 3 × 20 = 60 50 − 110 110 8 None 7 ♥ 7 7 × 30 = 210 1000 300 − 1510 1510 9 E-W 4 ♠ X 2 × ( 4 × 30 ) = 240 50 300 590 − 590 10 Both 2NT 40 + 30 = 70 50 − 120 120 11 None 6 ♣ 6 6 × 20 = 120 500 300 920 − 920 12 N-S 2 2 × 20 = 40 20 50 − 110 110 13 Both 4 ♥ X X 2 × 2 × ( 4 × 30 ) = 480 100 500 − 1080 1080 14 None 5 ♠ 50 − 50 50 15 N-S 4 ♥ 5 4 × 30 = 120 30 300 − 450 450 16 E-W 3NT 40 + ( 2 × 30 ) = 100 300 400 − 400 Comparing deals ( edit ) Matchpoint scoring ( edit ) The most common form of pairs scoring is by matchpoints . On each board , a partnership scores two matchpoints for each other partnership that scored fewer points with the same cards , and one point for each other partnership that scored the same number of points . Thus , every board is weighted equally , with the best result earning 100 percent of the matchpoints available , and the worst earning no matchpoints ; the opponents receive the complement score , e.g. an 80 % score for a N-S pair implies a 20 % score for their E-W opponents . Colloquially , a maximum matchpoints score on a board is known as a `` top '' , and a zero score is a `` bottom '' . The terms `` high board '' and `` low board '' are also used . Note 1 : using American Contract Bridge League ( ACBL ) methods , scoring is one point for each pair beaten , and one - half point for each pair tied . Note 2 : The rule of two matchpoints for each pair beaten is easy to apply in practice : if the board is played n times , the top result achieves 2n − 2 matchpoints , the next 2n − 4 , down to zero . When there are several identical results , they receive the average . However , complications occur if not every board is played the same number of times , or when an `` adjusted '' ( director - awarded ) score occurs . These cases can result in non-integer matchpoint scores -- see Neuberg formula . These matchpoints are added across all the hands that a pair plays to determine the winner . Scores are usually given as percentages of a theoretical maximum : 100 % would mean that the partnership achieved the best score on every single hand . In practice , a result of 60 % or 65 % is likely to win the tournament or come close . In a Mitchell movement ( see above ) the overall scores are usually compared separately for North - South pairs and for East - West pairs , so that there is one winner in each group ( unless arrow - switching has been applied - see above ) . Historical Note : At some time in the past , both North - South and East - West might be awarded the same matchpoint score . Using this arrangement , the lowest East - West Score would be the winner . In Board - a-match team game , the matchpoints are calculated using a similar principle . Since there are only two teams involved , the only possible results are 2 ( won ) , 1 ( tied ) and 0 ( lost ) points per board . International Match point scoring ( edit ) In International Match Point ( IMP ) scoring , every individual score is subtracted from another score , and the difference ( or `` swing '' ) is converted to IMPs , using the standard IMP table below . The purpose of the IMP table , which has sublinear dependency on differences , is to reduce results occurring from large swings . The score that is being compared against can be obtained in the following ways : In team events , it is the score from the other table ; In pair events , it can be : The datum score , most often calculated as the average score on board , excluding a number of top and bottom results . Sometimes , the median score is used instead . In `` cross-imps '' or `` Calcutta '' scoring , every score on board is compared against every other score ( sometimes excluding top and bottom results ) and IMPs summed up ( and possibly averaged , to reduce `` inflation '' ) . Example of averaged cross-imp scoring : Assume that you are one of five pairs who play Board 2 as N / S ( you are vulnerable ) . On this board you bid and make 4 Spades , scoring + 620 , while the other four N / S pairs score − 100 , − 100 , − 300 , and + 650 . To figure out your averaged cross-imp score , you would create a table like the Cross-IMP example table below : after writing in the scores of you and your opponents in the bolded areas , you would then fill in the Score Delta row by subtracting each of the opponent 's scores from yours . Then , you would fill in the IMPS Gained row by converting each of the score deltas into IMPS via the standard IMP table ( e.g. 720 equates to 12 IMPs , because it falls in the range of 600 to 740 in the IMP table ) . You then add up those numbers and get 36 IMPS . To turn the 36 IMPS into a averaged cross-IMP score , you simply divide that number by the number of competitors ( 36 IMPs divided by 4 competitors ) to arrive at 9 as your averaged cross-IMP score . Example of cross-IMP table Our score on Board 2 is 620 Scores of the four other North / South pairs − 100 − 100 − 300 650 Score Deltas 720 720 920 − 30 IMPS Gained 12 12 14 − 1 IMP table Point difference IMPs Point difference IMPs Point difference IMPs from to from to from to 0 10 0 370 420 9 1750 1990 18 20 40 430 490 10 2000 2240 19 50 80 500 590 11 2250 2490 20 90 120 600 740 12 2500 2990 21 130 160 750 890 13 3000 3490 22 170 210 5 900 1090 14 3500 3990 23 220 260 6 1100 1290 15 4000 or more 24 270 310 7 1300 1490 16 320 360 8 1500 1740 17 History of contract bridge scoring ( edit ) Scoring of tricks in no trump contracts ( edit ) In the 1932 Laws of Contract Bridge , no trump tricks bid and made , and undoubled no trump tricks made but not bid , score 30 , 40 , 30 , 40 , 30 , 40 , 30 . In 1935 this became 40 , 30 , 30 , 30 , 30 , 30 , 30 . Scoring of undertricks ( edit ) before 1935 1935 - 1987 after 1987 , for duplicate bridge , and after 1993 for rubber bridge not vulnerable , not doubled 50 each 50 each 50 each not vulnerable , doubled 100 , 150 , 200 , 250 , 300 , 350 etc . 100 , 200 , 200 , 200 , 200 , 200 etc . 100 , 200 , 200 , 300 , 300 , 300 etc . vulnerable , not doubled 100 , 150 , 200 , 250 , 300 , 350 etc . 100 each 100 each vulnerable , doubled 200 , 300 , 400 , 500 , 600 , 700 etc . 200 , 300 , 300 , 300 , 300 , 300 etc . 200 , 300 , 300 , 300 , 300 , 300 etc . Redoubled undertricks have always scored twice as much as the same doubled undertricks . The 1987 change , to the scoring of the fourth and subsequent non-vulnerable undertricks , was made after a hand in the finals of the 1981 Bermuda Bowl . Munir and Fazli , playing for Pakistan , bid skilfully to reach a vulnerable 7 hearts , which would have scored them 2310 . But their non-vulnerable Meckstroth then sacrificed in 7 spades on a weak hand with fives spades to the jack . This went nine off doubled for a score of - 1700 , a profitable sacrifice . The change of scoring increased the penalty from - 1700 to - 2300 . Also , the `` insult bonus '' for making a redoubled contract used to be only 50 . This was changed to 100 , so that playing 5 of a minor , redoubled , making an overtrick , is always worth more than an undoubled small slam . 8 - level bids ( edit ) It has always been the intention of every official set of Laws of Contract Bridge to forbid contracts for more than seven tricks . Some versions have stated this more clearly than others , but this intention of the Laws has never changed . International Match points ( edit ) When International Match Points were first introduced in Europe , they were as in this table . IMP table , 1949 Point difference IMPs Point difference IMPs from to from to 0 10 0 1000 1240 8 20 40 1250 1490 9 70 130 1500 1990 10 140 210 2000 2490 11 220 340 2500 2990 12 350 490 5 3000 3490 13 500 740 6 3500 3990 14 750 990 7 4000 or more 15 On September 1st 1962 they were changed to the table above . References ( edit ) Jump up ^ Official IMP Table ^ Jump up to : The Laws of Contract Bridge . de la Rue. 1932 . ^ Jump up to : The International Laws of Contract Bridge . de la Rue. 1935 . Jump up ^ The International Laws of Duplicate Contract Bridge . Bibliagora. 1981 . Jump up ^ The Laws of Duplicate Contract Bridge . The English Bridge Union Ltd. 1987 . Jump up ^ Jacobs , Bill ( April 2010 ) . `` ( untitled section ) '' ( PDF ) . Victorian Bridge Association Bulletin : 6 . Jump up ^ ( untitled leaflet ) . European Bridge League . Jump up ^ Laws of Duplicate Contract Bridge . de la Rue. 1963 . External links ( edit ) How to Keep Score - from the official ACBL website . ACBL Club results Contract bridge Overview General Auction bridge Bridge ethics Bridge - O-Rama Bridge maxims Bridge Murder case Bridge scoring Bridge whist Bridgette Cheating in bridge Chicago Computer bridge Contract bridge Contract bridge diagram Duplicate bridge Duplicate bridge movements Five - suit bridge Goulash Glossary of contract bridge terms High card by suit History of contract bridge Laws of Duplicate Bridge Masterpoints Minibridge Neuberg formula Rubber bridge Screen Singaporean bridge Suit Traveling scoreslip Trump Vugraph Bidding General Balanced hand Balancing ( bridge ) Bidding box Bidding system Board ( bridge ) Bridge convention Brown sticker Convention card Cue bid Five - card majors Forcing bid Forcing pass Game try Hand evaluation Honor point count Inverted minors Law of total tricks Losing - Trick Count Major suit Minor suit Optimum contract and par contract Overcall Preempt Prepared opening bid Principle of fast arrival Psychic bid Quantitative no trump bids Reverse ( bridge ) Sacrifice ( bridge ) Shooting ( bridge ) Single suiter Strong pass Takeout double Three suiter Two suiter Useful space principle Void ( cards ) Weak two bid Zar Points Systems List of bidding systems 2 / 1 game forcing Acol Bidding system Blue Club Boring Club Bridge Base Basic Bridge World Standard Canapé ( bridge ) Carrot Club EHAA Fantunes Highly unusual method Kaplan -- Sheinwold Little Major Moscito OKbridge 2 / 1 Polish Club Precision Club Roman Club Romex system Säffle Spade Standard American Strong club system Conventions List of bidding conventions Card play General List of play techniques Avoidance play Beer card Caddy Card reading Duck Endplay Entry Grosvenor gambit Hold up Percentage play Pin ( bridge ) Principle of restricted choice Probabilities Revoke Ruff Shooting Smother play Tempo Trump promotion Uppercut Vacant Places Declarer play Basic : Finesse Safety play Coups : Alcatraz coup Bath coup Belladonna coup Coup Coup en passant Crocodile coup Deschapelles coup Devil 's coup Loser on loser Merrimac coup Morton 's fork coup Scissors coup Trump coup Vienna coup Squeezes : Backwash squeeze Cannibal squeeze Clash squeeze Compound squeeze Criss - cross squeeze Double squeeze Entry squeeze Entry - shifting squeeze Guard squeeze Knockout squeeze Non-simultaneous double squeeze Progressive squeeze Pseudo-squeeze Saturated squeeze Simple squeeze Simultaneous double squeeze Single - suit squeeze Squeeze play Stepping - stone squeeze Strip squeeze Triple squeeze Trump squeeze Vice squeeze Winkle squeeze Suit combinations : Suit combination Suit combination -- J missing Suit combination -- 10 missing Suit combinations -- K10 missing Defender play Forcing defense Journalist leads Opening lead Rule of 10 - 12 Rule of 11 Rusinow leads Signal Smith signal People and organizations General ACBL Youngest Life Master List of contract bridge people List of nationality transfers in sport Players by country Australia Austria Brazil Britain Bulgaria Canada China Denmark Netherlands Egypt Fiction France Germany Hungary India Ireland Israel Italy Jewish players Mexico Monaco New Zealand Norway Pakistan Poland Russia Sweden Switzerland Taiwan United States Other lists Alphabetical list of contract bridge people with Wikipedia ( english ) articles List of bridge administrators List of bridge writers Teams Blue Team Dallas Aces Four Aces Clubs Bridge Club Brașov Cavendish Club Crockford 's Galatasaray Bridge Team Melville Bridge Club Portland Club ( London ) Savoy Club Young Chelsea Bridge Club Governing bodies American Bridge Association American Contract Bridge League Austrian Bridge Federation Brazilian Bridge Federation British Bridge League Canadian Bridge Federation Dutch Bridge Federation English Bridge Union European Bridge League Hungarian Bridge Federation International Mind Sports Association List of bridge governing bodies Norwegian Bridge Federation South African Bridge Federation United States Bridge Federation World Bridge Federation Championships General List of bridge competitions and awards World Bermuda Bowl Bridge at the 2008 World Mind Sports Games Bridge at the 2012 World Mind Sports Games Cavendish Invitational Computer Olympiad McConnell Cup Rosenblum Cup Senior Bowl ( bridge ) Triple crown of bridge Venice Cup WBF Youth Award World Bridge Championships World IMP Pairs Championship World Junior Pairs Championship World Junior Teams Championship World Mind Sports Games World Mixed Pairs Championship World Mixed Teams Championship World Open Pairs Championship World Senior Pairs Championship World Senior Teams Championship World Team Olympiad World Transnational Open Teams Championship World Women Pairs Championship National and Zonal Buffett Cup Camrose Trophy Commonwealth Nations Bridge Championships European Universities Bridge Championships Gold Cup ( bridge ) North American bridge Championships : ACBL King or Queen of Bridge Blue Ribbon Pairs Bruce LM - 5000 Pairs Chicago Mixed Board - a-Match Fall National Open Pairs Fast Open Pairs Fishbein Trophy Goren Trophy Grand National Teams Hilliard Mixed Pairs Jacoby Open Swiss Teams Keohane North American Swiss Teams Lebhar IMP Pairs Leventritt Silver Ribbon Pairs Machlin Women 's Swiss Teams Manfield Non-Life Master Pairs Marcus Cup Master Individual Mini-Blue Ribbon Pairs Mini-Spingold Mitchell Board - a-Match Teams Mott - Smith Trophy Nail Life Master Open Pairs National 199er Pairs National 49er Pairs National 99er Pairs Non-Life Master Swiss Teams Norman Kay Platinum Pairs North American Bridge Championships North American Pairs Red Ribbon Pairs Reisinger Rockwell Mixed Pairs Roth Open Swiss Teams Senior Knockout Teams Silodor Open Pairs Smith Life Master Women 's Pairs Spingold Sternberg Women 's Board - a-Match Teams Truscott Senior Swiss Teams Vanderbilt Trophy Von Zedtwitz Life Master Pairs Wagar Women 's Knockout Teams Wernher Open Pairs Whitehead Women 's Pairs Young LM - 1500 Pairs Publications and resources Books List of contract bridge books 25 Bridge Conventions You Should Know Bridge Squeezes Complete The Cardturner Design for Bidding Contract Bridge for Beginners Edwin Kantar bibliography Master Point Press Planning the Play of a Bridge Hand Terence Reese bibliography The Official Encyclopedia of Bridge Tickets to the Devil Magazines List of bridge magazines Bridge d'Italia Bridge Magazine The Bridge World External links Bridge Base Basic Bridge Base Inc . OK bridge 2 / 1 Retrieved from `` https://en.wikipedia.org/w/index.php?title=Bridge_scoring&oldid=833319315 '' Categories : Contract bridge Talk Contents About Wikipedia Español Français Polski Suomi 中文 Edit links This page was last edited on 30 March 2018 , at 20 : 55 . Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply . By using this site , you agree to the Terms of Use and Privacy Policy . Wikipedia ® is a registered trademark of the Wikimedia Foundation , Inc. , a non-profit organization . About Wikipedia

Question: when do you declare honors in contract bridge