A cap of the former Japanese Navy officer.
 It is from the time of the war. 

The outer material is made of blue-brown wool serge 
fabric, and the lining is made of ecru white 
cotton fabric.
Also, the cloth that rests on the head is made of
 blue-brown linen fabric.
Size indicated at the zenith
　　2　letter and
There is a name.
It says size 2,
It is approximately 27cm long when folded, and is 
thought to be about the size of a small-sized issue.
It is not a so-called business cap, but a combat
 cap worn when wearing 3rd class military uniform.
Two black twill side lines are sewn on to indicate 
an officer, and the front chapter has a late-model
 insignia for officers, with cherry blossoms, 
an anchor, and a wreath woven with yellow 
silk thread on a brownish-blue silk plateau. 
There are no air holes, and the rear adjustment 
hole uses two pairs of black eyelets.

How about military collectors?