There are a few. The most common are Shi****o, Fushimi and Yatsafusa. All are used in various preparation, although the Shi****o is mild, similar to the American Wrinkled Old Man or the Spanish Padron peppers.
The Shi****o is often used for tempura and other dishes where it would be eaten whole. The Fushimi and Yatsafusa are hotter and often are used in Togarashi, the Japanese pepper and spice blend used all over Japan, usually in place of black pepper.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"perhaps...but then again...maybe not..."