It's next to the handle tube. According to Yamaha official website's inquiry, every Yamaha trumpet sold will have a unique instrument number, next to the handle tube, which is a series of black mimeographed letters and numbers. Yamaha Co., Ltd. is a Japanese brand founded by Torakusu Yamaha on 1887, and its headquarters is located in Qianqiao City, Gunma Prefecture, Japan. Yamaha's products range from keyboard instruments such as piano, electronic organ and synthesizer, wind instruments such as brass and woodwind, stringed instruments such as violin and cello, and all percussion instruments to the most advanced professional audio equipment.