In our more than 30 years dealing with Japanese baseball cards, we have never before seen this card! It is obviously part of the JBR 25 set, given the card's dimensions and appearance, but it must not be a common as others in the set.
The American who changed Japanese baseball with his hard charging style of play, possibly resulting from his time as a running back with the San Francisco 49ers, makes a very rare rookie appearance with this card. Blank backed.
Size: 1 3/4" x 2 1/2"