These Japanese Die-Cut Baseball Menko Cards were made in c1948-1950.
This set is Uncatalogued in the Japanese Baseball Card Catalog.
When Catalogued they would probably be ranked R5,
meaning est. under 5 of ea. card known.
Kaoru Betto 別当 薫
is in the Japanese Baseball Hall of Fame
Betto was a player from 1948-1957, 1950 MVP
He was also a manager from 1952-1973
'The DUDE' in the movie 'The Big Lebowski' wore a Kaoru Betto shirt in movie.