[JJ McGraw]

I have a small collection of Japanese baseball items, 1900-1930’s, mostly cards, programs and photos. The baseball cap was like our cap in size , shape etc. The cap this player is wearing reminds me of the Japanese military fatigue cap, it fits the shape of one , has a narrower crown, etc. ( see photos below)
Also, the back caption was clearly written by an American GI, probably his guard, “Jap Baseball Player”, but the cap is the key.
My guess is, it could be taken in Japan, post war occupation and this “soldier” is still wearing his military fatigue cap. I agree the N is most likely for Nippon, and I think EFF , when they were making the real stuff, made a jersey similar to that one in the photo. Problem is, you can’t access the old info online.
That is my guess, hence the US jeep, barbed wire etc.