Japanese Bladesmithing

Bladesmithing is the art of blacksmithing that relates specifically to creating knives, swords, and other blades using a forge, hammer, anvil, and other smithing tools. Bladesmiths employ a variety of metalworking techniques used by blacksmiths, as well as woodworking for knife and sword handles, and often leatherworking for sheaths.

Bladesmithing is a branch of blacksmithing, thus most, if not all, blacksmiths will be familiar with bladesmithing as well as the other aspects of their craft, while bladesmiths will not necessarily be familiar with other aspects of blacksmithing.

Japanese bladesmithing stems from Chinese blacksmithing, and is often considered an extremely rigid, precise process, involving folding and forge-welding the steel many times over to create a laminated blade. In the past, it was typically assumed that more folds resulted in a higher quality blade. However, in modern times it is widely agreed that folding the steel past a certain point will actually decrease the effectiveness of the sword, resulting in a blade so thinly folded that it approaches the same effectiveness as a solid piece of metal with no folds at all. The number of folds that 'optimize' the blade toughness and edge-holding ability vary between smiths and between blade thickness and types of metal.

Often Japanese bladesmiths would forge their blades out of multiple materials, rather than simply folding and forge-welding one type of steel to itself. Wrought iron, which is very durable and less brittle than steel, would sometimes be used for the spine of the blade, with extremely hard high-carbon steel forming the blade's edge. This process creates a highly impact-resistant blade with an extremely sharp edge. However, under heavy usage, the edge would be more prone to chipping than its European counterparts, which were typically designed to deal with heavier armor than Japanese blades.

It is often mistakenly believed that two famous swords, the Muramasa and Masamune katanas, were forged in medieval Japan. The mistake in this belief is that there were in fact multiple "Masamune" and "Muramasa" swords forged in medieval Japan, as these were names of swordsmiths who produced various works, all of which could be called a "Masamune" or a "Muramasa" depending on which maker forged the blade. The sword most traditionally referred to as "The" Masamune is the Honjo Masamune, a national treasure of Japan.