We do not know which bromide set is associated with this 1st prize winner bromide card, but we do know from the text on the card that the image commemorates Hiroshi Oshita's 100th lifetime home run. As corroboration, we see Oshita wearing a uniform used by the his team, the Flyers, only in 1950. From looking at Oshita's year-by-year statistics, we see that his 100th homer was hit at some point during the 1950 season. Oshita was generally regarded as the best hitting outfielder in Japan Pro Baseball during the early postwar years.
Blank back card
Size: 8 1/4" x 11 1/8"
Condition: Some creasing. Overall G/Vg. There is extra paper and glue residue on the blank back due to the card being originally offered attached to a product display sheet by the manufacturer. All examples of this card should exhibit that characteristic.