Privately made cases used to protect medal sets during transport.
These cases below are called 'Field Cases' in Japanese. I am not sure
how many soldiers would carry medals to the field, but perhaps
higher-ranking officers would to prepare for photo ops.
The two I have shown here are for the Golden Kite medals. The outline
shows that it would hold the 5th Class or above. I have seen other cases
for the Sacred Treasure and Rising Sun medals, too.
3rd Class Order of the Rising Sun with a
leather fitted carrying case.