What is Itame Hada in Japanese Katana terminology?

"Itame Hada" or 板目肌 in Japanese, refers to a pattern on the surface of the ground iron (jigane) of a Japanese sword that resembles the grain of wood planks. This pattern is commonly seen on many Japanese swords.

The larger patterns are referred to as ""O-Itame"" and are often seen in the Soshu tradition (Soshu-den). On the other hand, the smaller patterns are called ""Ko-Itame"", and they are characterized by a densely packed ground iron.

The Soshu tradition is one of the five main traditions of Japanese swordsmithing, known for its bold and innovative style. The densely packed ""Ko-Itame"" pattern is considered to be of higher quality compared to the larger ""O-Itame"" pattern.

In general, the pattern of the ground iron (jigane) plays a significant role in the aesthetics and value of a Japanese sword. It is one of the factors that sword connoisseurs look at when evaluating a sword.