My great grandfather got this in ww2 can someone tell me what it is and if its rare or not.I've never seen the flags on any other sword

[caseiscool]

[lonely panet]

Manchuria aka manchuko occupational sword. Appears very strongly a original piece 

[Bruce Pennington]

Agreed.  Dawson says this model was for "Japanese patrolmen and sergeants and with the swords authorized for Japanese naval prison guards and shore patrol sailors.....authorized for enlisted men in the Manchukuo Imperial Army."