High Manganess steel refers to carbon steel with manganese content of more than 10%. High Manganess steel forged samurai swords have excellent toughness, extremely sharp, not easy to break, suitable for forging high quality samurai swords. coolkatana offers cost-effective katana forged from High Manganess steel. All are designed for practical use, and the products are hand forged by swordsmiths who have inherited two hundred years of casting technology in Longquan, China.