c = core steel
o = outer steel
Reverse wrapping = GYAKU-KOBUSE
The Kobuse steel is constructed of two different kinds of steel, the core steel and the outer steel, where the core steel is wrapped with the outer steel. As to the tempering, the outer steel is more sensitive than the core steel. The outer steel was made of damascus folded steel, it was folded 13 times creating 8192 layers for superior strength and flexibility. The visible tenuous undulating grain pattern (HADA) on the blade was resulted from folded repeatedly during forging. The core steel was made of 1095 high carbon steel providing the internal structure that is hardened with the 0.95% carbon content.
Our Kobuse steel has been throughly refined and tempered, a special clay is applied to the blade by hand, using a thin covering near the edge and a thicker layer over the rest of the blade. This results in a relatively quicker cooling of the edge during quenching, producing a hard edge and softer back. The beautiful real hamon on the blade is also result of the differential cooling of the blade (quenching and tempering). The blade has been hand polished with multiple grade sharpen stone by Japanese methods, which made the surface of the blade like a mirror, the more importance is that the blade was polished by HAZUYA which is a very thin Uchigumori stone fixed with paper. Hazuya is a specific stone to bring up hamon, the stone is very fine and soft against the steel.
The Kobuse steel combines the two powerful methods to create a katana sword that is hard at the core yet durable to avoid breaking on the outer layer, this kind of blade is top quality in our store and the best for cutting.