Japanese WWII Relic Battle Damaged Helmet Shell

Original period manufacture. A crusty example found on one of the Pacific Islands during aircraft recovery in the 1980's. We purchased this from the man who was involved in that project but sadly he did not remember on which Island it was found. Standard IJA steel helmet with a bullet or shrapnel strike on the rear edge. All three of the suspension liner loops are intact and the shell still has a ring to it when lightly struck. Two rust holes in the crown.