Asian coal briquettes
, also known by the names  () or fēngwōméi (), are coal briquettes used in East Asia for cooking and home heating. They were first invented in Japan, then propagated through the rest of East Asia in the early 20th century, although they are now uncommon in Japan and South Korea. Made from a mixture of lignite coal dust and a gluing agent that keeps the dust particles together, they became a popular alternative to firewood and natural coal because they come in a consistent size and stack easily. There are 5 standard sizes for the briquettes, and the 2nd standard is widely used in households. The 2nd standard briquette is cylindrical in shape, weighs , and is about  in height and  in diameter. The standard briquette has 22 holes drilled into its top to facilitate steady, efficient burning, and a household typically uses one to three briquettes per day in the winter. A new briquette can be placed on one that has been burned halfway to extend the burn time. The same fire used for cooking also served to heat the house, through a Korean radiant underfloor heating system called ondol. History by region

Korea 
Introduced to Korea from Japan in the 1920s,  rose in popularity following the Korean War. By 1988, 78% of Korean households used , but this fell to 33% by 1993 as people switched to oil and gas boilers, and was estimated to be used by just 2% of households by 2001. The boilers reduced the risk of carbon monoxide poisoning, which was a major cause of death in coal-heated houses. In recent years amid South Korea's suicide epidemic,  has seen use as a method of suicide by carbon monoxide poisoning. References

Heating
South Korean culture
Japanese culture
Coal in South Korea
Coal in Japan