Masakage Koishi knives. Handmade by Kato san, the Masakage Koishi collection is handmade with Aogami Super steel and hardened to 63:65 rockwell. The knives use san mai construction and are clad with stainless steel. The octagonal handles are made with Cherry wood with pakka wood ferrules. The name Koishi means pebbles and the name comes from the tsuchime (hammered) finish which gives the impression of river pebbles. These are the top performing line from Masakage with the hardest, most long lasting edges they make.