Japanese traditional forged knives are shaped using hammers and simple forging dies. This traditional process normally starts by heating and forge welding a piece of high carbon steel to an iron bar or mild steel bar and the blade is then hot forged to shape, rough ground, heat treated, ground to final shape and sharpened.
This manufacturing approach requires a lot of skill and involves a large number of processes, but it wastes very little metal and it is well suited to the production of custom knives and small batches of knives, particularly if they are made with expensive high carbon steel alloys. These methods also allow a small smithy to produce a wide variety of blade designs without investing in expensive machinery, fixtures and jigs.
Many contemporary traditional Japanese smiths continue to use techniques that have been passed down for many hundreds of years, from the era of the great Samurai sword smiths.