The NIKKAN CR-231, serial number "911121," is a cornet manufactured by Nippon Kan-gakki Co., Ltd. (NIKKAN), the musical instrument manufacturing division of Yamaha. [It is estimated that the manufacturing date was September 1977.] This model is a long-type cornet made of yellow brass with an engraved bell. I don't know much about it (I've never played it), but the moving parts function without sticking. It has been stored for over 30 years. (I haven't maintained it.) The photos are everything. Thank you for looking.