All About Pocket Knives

This bayonet has an OAL of 20", the blade is 15 1/2". Both sides of blade have a long fuller. Handles are a hardwood held on by 2 screws and 4 'washers'. All looks to be in original condition.
On one side of tang are 4 small overlapping circles and on the other side has 3 ? characters that are hard to make out. It might be 2 "H"s and a stylized eagle, or else characters not from our alphabet.
Can anyone ID this bayonet as to country of origin and approximate age ?
thanks, kj

Looks Japanese, WW2 era.

Japanese Type 30 bayonet. Made at Kokura arsenal Tokyo.

Thank you both. I never would of thought "Japanese". I was thinking German or Turkey or whatever, but not Japan.
Are these common ? Does it have much value ?
kj

Rather common - there are 98 active auctions on fleabay as I type.

I see with scabbard these are getting over $100 on ebay auction. So maybe $50-$75 without scabbard ? It is a good 'home self defense' piece.
kj