[2][3] The flat cooktop counter or hearth installed over the agungi is called a buttumak (부뚜막).

[6] Iron and ceramic buttumaks, similar to their later forms, were excavated from Goguryeo 1st century BCE historical sites, such as Anak Tomb No.

[3] Buttumaks in agrarian Korean kitchens were commonly made from brick or stone and then smoothed with clay.

[5] Agungi and buttumak are among the main components of the traditional ondol (floor heating) system.

Vents in the back of agungi are opened on cold days to allow the smoke and hot air flow through the flues underneath ondol rooms and exit into the chimney at the other end of the house.