B-bozu Nezumi Kozou Dai!
is an early and obscure Sanrio
character, introduced in the year 1984
, when the company was experimenting with a wide range of new characters. Even though Nezumi was manufactured through to the year 1999
, he has not survived as an enduring Sanrio character, unlike Hello Kitty
or Bad Badtz-Maru
B-bozu Nezumi Kozou Dai!, translated to English, is "Hey! I'm Kozou Mouse!"
Nezumi's favourite passtime is making hikaru dorodango, which are essentially large marbles, made of mud, polished to a deep shine. "Dango-making" was a national craze throughout Japan's pre-schools in the mid-1980s. The character was created by Sanrio to take advantage of this craze.
Nezumi-chan's best friend is Kiku-chan (who never became a fully-fledged Sanrio character). Nezumi-chan's birthday is March 3rd.
Research sources: Sanrio homepage (Japanese) & Japan Information Network/Japan Echo / shro0m