A tokkin kodaidai is a stand with a protruding central portion that resembles the kabukin worn by yamabushi (mountain priests). In other words, the inside of the base is carved in the shape of a bine, as if the hats of the mountain priests were turned down. If the inside of the base is cut in the opposite direction, it would not only be unnatural but also might cause the bottom of the bowl to be cut off.
This is a popular term used by the Jingdezhen pottery industry in China. It refers to the foot of the bowl (tadai).
The sound is Atsu. This character is not found in any Chinese character books.