The original Japanese release (or OJR for short) was one of the largest and longest-lived Zoid releases to date and is often looked upon as the 'true' Zoids line. Like many other toy lines, Zoids is set in its own universe and this is where three factions battle for control of the Planet Zi; the Helic Republic, the Zenevas Empire and the Guylos Empire. Each side has its own strengths, weaknesses, characters and of course, Zoids. A battle story details the faction's movements in full and this continues in the current line of Zoids which contains many re-released OJR models.
Each model in the Japanese line was given its own designation number which can be decoded as follows:
Prefix R = Republic Prefix E = Empire Prefix D = Dark
MZ = Motorised Zoid PZ = Powed Zoid (takes AA size batteries) BOZ = Battery Operated Zoid (takes large C size batteries)
Thus, RPZ-001 can be read as 'Republican Powered Zoid No. 1.