Language: Mandarin Chinese
Origin: Historical literature
Jiāgāng (加鋼) literally means "to add steel" or "added steel". It refers to a construction of edged weapons where a separate piece of high-carbon steel is forged into layers of milder steel. When the blade is then quenched, the high-carbon plate forms crystals that makes it hard but brittle while the other lower carbon layers remain tougher and more resilient.
A jiāgāng construction on a Chinese saber. The darker steel at the edge is the inserted high-carbon edge plate.
The term is used among others in the Gongbu Junqi Zeli (工部軍器則例) of 1815. This is an imperially commissioned text on the manufacture of arms by the Board of Works for the Qing military.