Helmet translation

[ViniVidiDejaVu]

Greetings! I have a WWII Type 90 Japanese helmet that has the original kanji painted inside the flare. I am hoping someone can help identify this soldier and any other information that the kanji may provide. Thank you for your help!

Mike McClain

 

[Toritoribe]

藤本大
Fujimoto Masaru

大 could be an abbreviation of a given name starting with 大 (e.g. 大介, 大五郎,,,).
The first one "katakana オ in a circle" would be a mark for something.

 

[ViniVidiDejaVu]

Thank you!