Katou means "with added carving." These coins are made from a Chinese circulating coin which has been retouched with a knife. This can be done to make the characters sharp once again, bit it also changes the shape of the characters. Below are varieties of katou bita sen recognized in the Japanese book Honpou bitasen zufu (Anasend� 1982), and some unlisted varieties. Junpei Genpou, katou This is based on the Northern Song Ji Ping Tong Bao. This is a katou-bitasen. The Ji character has been recut and changed to look somewhat like the character "jun" 順 . The characters connect with both the inner and outer rims, as is common with bitasen. There are rarer varieties of this coin where the minter has cut a circle around the inner part of the outside rim in order to separate the characters from the rim. I bought this in a flea market in Kochi.