In that foto what we are looking at is just the forging for the blade, the gonjo is a separate forging. There are a number of ways it can be produced:- a piece of the pamor before the core in welded in can be cut off and forged to make a gonjo forging; the same thing can be done after the core is forged in; a separate forging entirely can be produced, sometimes plain iron, sometimes with a miniaturisation of the blade pamor, sometimes with a different pamor.
Yes, in the making of the blade, all the work after the forging has been produced is cold work; you actually carve the blade from that forging. However, at some points in the making you do need to go back to the forge and use heat to create what you set out to create.
|