Harenchi Gakuen

Harenchi Gakuen is a sexy gag media franchise that was Go Nagai's first success in the manga business. It introduced the 'Ecchi' genre to manga and anime, and became an influence on later works by Nagai and other manga artists despite the amounts of criticism it received. Several manga, OVA, and live action adaptations were spun off from this series.

Summary
Harenchi Gakuen is mainly about the several scandel-ridden misadventures of Yasohachi "Oyabun" Yamagishi, Mitsuko "Jubei" Yagyu, and their friends both in and out of school. The series had expanded in both sequels and spin-offs with events like Oyabun and Jubei getting married and Jubei acting as a professional golfer.

Harenchi Gakuen in Mazinger

 * Revealed in an interview with Nagai, the designs for Koji Kabuto and Sayaka Yumi were originally of several designs for Oyabun and Jubei respectively.
 * In the original Mazinger Z manga, Boss mentions the Gakuen School before Jubei herself appeared for a few slides.
 * This is referenced in Episode 10 of Mazinger Edition Z: The Impact!, when Ankokuji says the Kurogane House has turned into Harenchi Gakuen when he informs Tsubasa Nishikiori of the destruction caused by the Gamia Q assassins.
 * Ayu from a few chapters from Harenchi Gakuen makes a cameo in God Mazinger as the grandchild of a Hino Elder.