I had one collector reply to me:
Yes, it's real. Presented to Mr. Honma Mitsuyoshi
忠勇
Loyalty and Bravery
祈武運長久
Prayers for continued success in the fortunes of war
本間光吉君
Honma Mitsuyoshi-kun
Mr. Honma, Mitsuyoshi
I'm taking a leap of faith that kanji is 光 although it looks like 士儿 . Here's one interpretation of 光 in "grass writing" from which I base my guess: There are other slogans similar to 必勝 [certain victory].