OK, after a more thorough investigation (which involved a Japanese woman and two LtCols from the Japanese Self-defense force), the following is submitted:

The first kanji character is called 'dai'- (pronounced die) and means big
the second two are #s- 4 and 2.

The best guess is the first kanji symbol is probably someones name or a unit name in a shortened/abbreviated version (I can give you the explanation of the Japanese language, but it's long and confusing and will require a beer or three...bottom line is you generally need a context to translate the characters, and there really is only conjecture on that context here) and the second and third symbols are simply #s.

Hope this helps.