You are correct, this was the first series of cartridges Ikeda designed for his new company Ikeda Sound Lab, after the demise of Fidelity Research. As far as I know it is the only cantileverless MC in the history of audio.
The design matched the shape of the Ikeda headshell and came in a range of different colours. The top models had an integrated headshell (similar to the earlier Fidelity Research FR7 series), called the Supremo and the Musa. The gold coloured version was the top of the ’normal’ range, called Rex. The version with the Kanji character seems to have been a variation of that, perhaps aimed at the domestic market. But this is somewhat unclear. There were also versions made for the Jeff Rowland and Cello brands (in gold and silver colour respectively).
Either way, you have one of the best cartridges ever designed. So if it is still up to spec and the stylus is okay you are in for something truly special. Enjoy!