What is Midarekomi Boushi in Japanese Katana terminology?

The term "乱込帽子" (Midarekomi Boushi) refers to a type of tempering pattern on a Japanese sword where the pattern becomes irregular from the Yokote line upwards, regardless of whether the blade pattern is straight or irregular. The condition of the blade pattern on the tip (kissaki) is used to determine whether it is a Midarekomi Boushi. This pattern is often seen in the works of swordsmiths from the late Kamakura period to the early years of the Nanboku-chō period. The "Midarekomi Boushi" is a unique and artistic expression of the swordsmith's skill, and it is highly valued by sword enthusiasts and collectors.