As the number of company rugby teams across Japan that joined the JRFU increased, the Japan Company Rugby Football Championship became enriched and boosted its popularity. The 1st Japan East Rugby Football Union Championship was held with only three teams from Kanto, Kansai, and Kyushu (the Tohoku and Hokkaido team resigned). From the ninth championship in 1956, however, the championship expanded in scale to 16 teams from all over Japan. Yahata Steel Works won this championship four consecutive years from 1955. The champion changed quickly after 1966, as follows: Kintetsu, Kintetsu, TOYOTA, Kintetsu, Kamaishi and Ricoh (shared the title), Mitsubishi Kyoto, Ricoh, Ricoh, Kintetsu, and Mitsubishi Kyoto. Company rugby entered an era where rivals based mainly on Kintetsu and Ricoh competed fiercely for the title.
In 1967, rugby fans were fascinated and swept by a series of excitingly competitive matches, represented by Kintetsu HO Tadashi Nakayama (Hatakeyama) who scored a come-from-behind try by running solo just before full-time. Rugby fans were also enthralled by active and brave performances of ruggers shown by the Japan National Rugby Union Team players that defeated the Junior All Blacks in New Zealand, Kintetsu players including Morio Kawasaki, Hiroshi Ogasawara, Yoshinori Okubo, Yoshihiro Sakata, and Koji Ishizuka, fantastic Ricoh players such as Mitsuo Atokawa, Yoshiaki Izawa and Tadayuki Ito, TOYOTA's Masayoshi Ozaki and Masaharu Mantani, and Akira Yokoi played for Mitsubishi Kyoto. This championship was supported by Asahi Shimbun, and broadcast by TV Asahi. During this period, while university rugby based on Waseda and Meiji was enthusiastically supported, company rugby made a giant leap in parallel with the boom in the Japan Rugby Championship where company teams competed with universities.