In 1991, Yamashita left Loudness; it was rumored that he did not get along with lead singer Mike Vescera, who replaced Niihara in 1989. After leaving Loudness, he worked on side projects, including Spaed and Blood Circus. He returned to Loudness in 2001.

He first started playing bass in a band called Black Rose. A short time later, his childhood neighbor and close friend, Akira Takasaki, invited him to join Loudness in 1981.

Masayoshi Yamashita (山下 昌良 , Yamashita Masayoshi) (born November 29, 1961 in Osaka, Japan) is the original and current bass guitarist of the Japanese heavy metal band, Loudness.