Japanese baseball badge. Latin phrase meaning "A sound mind in a sound body."
Pure silver badge dated 1931.
Baseball badge dated 1917.
Baseball badge dated 1930.
The obverse shows a baseball diamond with some
gold insignia above.
Marked sterling silver.
Dated Showa 11 .
It appears as though this was for a baseball tournament commemorative the wedding of the
Imperial Crown Prince of Japan (currently the Heisei Emperor) in 1959.
'Baseball tournament 1921.'
Osaka Autumn Tournament 1953
Osaka Spring Tournament 1953
Osaka Spring Tournament 1957
Osaka Tournament 1967
Osaka Tournament 1966
Osaka Tournament 1971
Baseball in Japan has a long, rich history. Consequently, badges for the sport are
plentiful, most of them being tournament or school club badges. It is of use to note,
however, that there is also a 'soft baseball' sport often played at schools. The kanji to
identify this sport are 軟式 (nanshiki), which preface the phrase for baseball: 野球 (yakyū).
The difference is singular: the ball in baseball is made of cork while the ball in soft
baseball is made of rubber. The rules are the same (as far as I know).
Soft baseball began in Japan in 1919, in order to give younger children a safer game to
play. After its introduction, participation in the sport allegedly skyrocketed.
Here is a portion of the Wikipedia article about the history of baseball in Japan:
"Baseball is one of the most popular sports in Japan. It was introduced to Japan in 1872
by Horace Wilson, who was an English professor at the Kaisei School in Tokyo. The first
baseball team was called the Shimbashi Athletic Club and was established in 1878."
See more HERE.
Soft baseball (rubber)
The reverse has kanji reading '2595 
Sendai 2nd Middle School. Baseball Club.'
Diameter about 3.5 cm.