On January 18, 2003, the oldest national flag of Japan (although it was not a national flag at the time) remaining today, which was granted as an Imperial gift by the Emperor Godaigo, and yosegaki (a card on which people write a few lines each) by Tenchu-gumi, and other items were stolen.
2003年（平成15年）1月18日、後醍醐天皇に下賜された現存最古の日本の国旗（当時は国旗ではなかったが）や、天誅組の寄せ書きなどが盗難にあった。