Can anyone tell me the specific name of this bomb used in world war 2? The Chinese writing on the bottom translates to ‘Nine Days’
It looks like a High Explosive artillery shell, and the short length of the cartridge makes me think it was for use with a mountain gun. Have you measured the diameter of the shell? I would suspect it is 75mm.
Maybe have a look at 53mm Hotchkiss rotating cannon shells. Appears to be a good comparison with that unusual ribbed fitting. ( An Introduction To Collecting Artillery Shells And Shell Casings - International Ammunition Association )
The Chinese Navy obtained it´s first specimens in 1875 - in this respect, any production year is conceivable. However, "Year Nine" could provide a clue to the production year.