July 10, 1971 The first fun work series<
It was “No.1 high speed gear box set” and “No.2 torque gear box set”.
Fun Work Series Catalog” published in 1977. Up to “No31 Tsunawatari Doll” was posted.
The “Fun Work Series Application Collection” was included with the “Fun Work Series Catalog” as an in-house publication. It started in 1977 and continued until the 8th collection.