Appreciating Japanese Swords
 - 刀剣ワールド

Depending on the historical background and the fighting methods, the overall appearance of a sword might be graceful, or perhaps majestic.

This is where the individuality of the swordsmith is most apparent, and the more you learn about its subtle changes, the more intriguing it becomes, like a starry sky.

The color of the steel and other aspects of Japanese swords appear differently due to the steel production techniques of each era.

Due to the fold-forging process of orikaeshi tanren , the jigane’s hada has 32,768 layers. Through different forging methods, mokume–hada, itame–hada, masame–hada, and other grain patterns become intricately woven together.

Aim to appreciate Japanese swords while referring to these three points.

At first glance, Japanese swords look the same, but they actually differ greatly in appearance depending on the era. Each era had different ways of fighting, and these swords were changed to fit them. Therefore, if you learn what each era’s swords look like, to an extent you can identify their time period by appearance alone.

The hamon are the shining patterns on the tempered edges of Japanese swords’ practical yet beautiful blades. They bring together the aesthetic, individual expressions of swordsmiths.

There are two main types of hamon: suguha and midareba. The former contains straight lines, while the latter is composed of various curved lines. Hamon are very artistic and capture viewers’ attention.

Seeing Japanese swords for the first time, they feel quite beautiful, as if one is looking at the shining stars of the Milky Way in the night sky. This comes from the shimmering white rhythmic dynamism and simple tension of the hamon on the clean, lean tōshin that combines practicality and beauty.

There are numerous secrets behind the creation of Japanese swords’ hamon. Full of mysterious energy, they are created by the chemical changes in heat treatment, in which the red-hot tōshin is placed in water. The hardest part of a Japanese sword is the hamon area.

To make a hamon, one applies a special clay called yakiba–tsuchi, thinly on the part that will become the hamon and thickly on the part that will become the jihada, and then cools the heated tōshin rapidly with water to make the hamon appear.

The jigane refers to both the steel material itself and the pattern of kitae–hada that appears when the steel is folded and forged.

It takes about 10 kg of steel to make a Japanese sword. When finished, the sword weighs less than a tenth of that, 850 to 900 g. Orikaeshi tanren is typically carried out fifteen times, which results in the jigane having 32,768 thin layers of steel, increasing impact resistance and doubling the sword’s strength. This is similar to how plywood is difficult to break.

The steel material contains a considerable amount of impurities. Referred to as slag, it is separated out by striking the steel, producing sparks. As a result, the forged-welded surface takes on a mokume–hada, itame–hada, masame–hada, ayasugi–hada, or other basic grain pattern, but there is rarely only one type; they usually mix together.

When viewing Japanese swords, the kitae–hada is something to note, as the forging differences between traditions and schools became apparent. A texture in which the individual parts of the forging structure are clearly visible is described as hada tatsu, while a texture in which the forging structure is denser is referred to with the phrase hada ga tsumu.

Itame–hada is the most common pattern found on Japanese swords, with large patterns called ō–itame–hada, small patterns called ko–itame–hada, and even finer patterns called nashiji–hada.

The Soshuden made pieces with ō–itame–hada, and in the Kamakura period (1185-1333), swordsmiths of the Yamashiroden often produced swords with dense koitame–hada.

There are very few Japanese swords with only mokume–hada. It is usually found in Bizenden and Bitchu Aoe-ha swords combined with itame–hada.

Masame–hada is the oldest grain pattern. Most of the jokotō, swords that existed before the swords today referred to as “Japanese swords” (Nihontō), feature it. The Yamatoden, the oldest Japanese swords tradition, inherits this style. Ayasugi–hada is a variant of masame–hada, and is often found in Oshu’s Gassan and Satsuma’s Nami no hira. The latter appears to be closely connected to Oshu.