The official Dragon Ball website’s twenty-eighth entry in “The Nearly Complete Works of Akira Toriyama” — an on-going series highlighting rare and important pieces of the author’s work over the years — is Toriyama’s contribution to the cover of the 1999 No. 37-38 double issue of Weekly Shōnen Jump (originally released 10 August 1999), selected for today to coincide with “Cat Day”:

The issue featured Toriyama’s second chapter in the Neko Majin series, Neko Majin Ga Iru 2 (“Neko Majin is Here 2”).

Toriyama’s corresponding author comment this issue lamented his increasing age:

A few years after completing Dragon Ball, and sporadically over the next few years in between his other projects, Akira Toriyama released chapters of Neko Majin, a series that increasingly became a Dragon Ball parody and spin-off as it went on.

Chapters were published between Weekly Shōnen Jump and (the now-defunct) Monthly Shōnen Jump, sometimes entire years apart from each other. The series consists of two chapters of Neko Majin ga Iru (“Neko Majin is Here”), one chapter of Neko Majin Mike, and five chapters of Neko Majin Z. The final two chapters of Neko Majin Z bucked the trend and were published back-to-back in consecutive issues of Monthly Shōnen Jump.

All eight chapters were collected into a single volume in April 2005. The volume was printed at the same size and quality level as the Kanzenban release of the Dragon Ball manga. They were later released in a newly-colorized version on 04 April 2013 (with no monochrome version available) for ¥450 plus tax via Shueisha and their digital offerings.

So far, the only chapter ever to be officially published and released in English has been Neko Majin Z 5, which was printed (without a chapter number) in the October 2007 issue of Viz’s (now-defunct) print version of Shonen Jump.