A small kiln inside a mansion. In other words, it is a small and simple kiln like the Raku and Nishiki kilns, and is similar to an unglazed kiln. Other honyaki kilns are outdoor oriented and are called yama-yama (mountain kiln) because the location is called “what-yama” (mountain), whereas nai-yama is the opposite term.
The inner kiln is used like the saggars of the honyaki kiln.
