Real name: ジャックス

Effective period / Period of releases: 1968 - 2008

Members: Hiro Tsunoda, Takasuke Kida, Haruo Mizuhashi, Yoshio Hayakawa, Suehiro Takahashi, Hitoshi Tanino

In the summer of 1965 Yoshio Hayakawa, with Suehiro Takahashi and Eiri Matsubara formed a group called Nightingale. The same members appeared on a Fuji TV show in the summer of 1966 under the name Windmills. Sometime shortly after this, Matsubara left and the group changed their name to the Jacks.
Hitoshi Tanino joined in January 1967, and Haruo Mizuhashi and Takasuke Kida in May 1967. The group released their first single in March 1968. Mizuhashi quit in September 1968, and was replaced by Hiro Tsunoda.
The group finally split up in August 1969.