Indonesian experimental bayonet or a Japanese experimental child training bayonet. ? (No ref.)

Indonesian experimental bayonet or a Japanese experimental Child training bayonet (?). Excellent bright finished plain blade. No markings. Darkened steel hilt with a ferule and a large pommel riveted by 4 steel rivets to the wooden grips. Unfinished (?) slot in the pommel. Rectangular opening in the top of the pommel. Two round openings on the sides and one large opening in the lower part of the pommel. Two excellent wooden shelves fixed to the blade tang by a single brass rivet. Steel crossguard with a forward swept quillon and a very small muzzle ring. MRD 1,1 cm. (Prob. to fix the bayonet over the cleaning rod.)
No scabbard.
Total length: 41,5 cm.

Very curieus bayonet!. The identification is speculative. It also could be an Indonesian made experimental bayonet.
Please let us know if you know what this is.