Hamokiri is specifically used for filleting Hamo "Japanese Daggertooth pike conger". This knife is also called Hone-kiri and literally translates to Bone Cutting.
The knife is wide and long enough to cut the small bones by the weight of the knife under a technique called "Honekiri" that leaves the skin connected. The knife crushes the fish's long hard bones by making 1mm cuts in the flesh without cutting the skin underneath.