Another dabbler in Japanese cards here. Have two or three small stacks of mostly ungraded menkos, bromides and whatevers. Love the funky aesthetics. Wouldn't dream of collecting a set. Too esoteric for me, brah. No can handle.
'30s Menko
Kaoru Betto abides
1950 Bromide
1950 Shonen premium (approx 6x9)
ETA: To the OP - Avail yourself of Robert Klevens' Prestige Auctions. Robert posts here, is a super nice guy, and is walking encyclopedia of Japanese baseball. He conducts small auctions several times a year. Always has interesting stuff. As far as I know he has a table at the Chicago National that is going on at the present time. One of my regrets of missing this year's event is not spending a pleasant half-hour chatting with Robert whilst eyeballing the cardboard.