A small, rectangular Japanese gold coin, first issued in 1599. It was the fourth part of a Ryo, and bears the inscription, Ichi Bu, meaning one Bu. The Bu was also divided into four parts, each one being called Shu.
The silver Bu was introduced in 1830, and continued in use until the introduction of the Meiji currency in 1870.
See Also: Bu
Source: Frey's Dictionary (American Journal of Numismatics, Vol. 50, 1916)