East Asian coal briquettes

East Asian coal briquettes (練炭), also known by the names ' or fēngwōméi' (, literally "beehive coal"), are coal briquettes used across East Asia for home cooking and residential home heating purposes. They were first invented in Japan, then propagated through the rest of East Asia in the early 20th century, although their usage is now uncommon in contemporary 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 3.5 kg, and is about 20 cm in height and 15 cm 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.

In older South Korean homes, the same fire used for cooking also serves to heat the house, through a radiant underfloor heating system called ondol.

Korea
Introduced to Korea from Japan in the 1920s, rose in popularity following the Korean War. By 1988, 78% of South 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.