Types of kissaki (tip) and mune (back)
Strictly speaking, the Kissaki is the area delimited by the yokote, the ko-shinogi, the fukura and the munesaki.
There are several types of kissaki. The most common are, in order of length, the Ko-kissaki, the Chu-kissaki and the O kissaki. The Ko-kissaki, the shortest, was mainly produced at the end of the Heian period up to the early Kamakura period and was mainly found on the tachis. The Chu kissaki, of medium length, is the most common. Present at all periods since mid- Kamakura, its middle size is very popular. The O-kissaki is much longer. It has a less harmonious appearance as regard to the rest of the blade, and it has a more aggressive look. It is especially encountered in the Nanbokucho, Shinto and Shinshinto periods.
There are also other types of kissaki, but less common. The kamasu kissaki (also called "barracuda" in reference to the fish shape) has a short fukura (see below for the explanation of fukura) and is similar of most chokutōs as regard to the tip (straight blades forged before the 10th century) and some blades at the beginning of the Koto period (therefore present for kiriha-zukuri structures).
The kissaki ikubi, found in the middle of the kamakura period, is very short (generally shorter than the saki-haba, width of the blade at the level of the yokote).
At last, the Kissaki moroha zukuri (or Kogarasu zukuri) is a rarer double-edged kissaki. It was inspired by the Chinese Jians (type of sword also commonly called "Gentleman of Weapons") and mainly present during the Nara period (710-794). The best known saber with this shape is the Kogarasu-maru attributed to Amakuni Yasutsuna, father of the tachi.
The surface of the kissaki (roundness of the tip) is also largely influenced by the length of the fukura. We are talking about fukura-kareru (fukura showing little, quite incisive, often present on tanto) and fukura-tsuku (rounded and therefore standing out more, thus increasing the solidity of the kissaki in general, as well as its surface, and it is the most current form of Futura).
The mune or back of the blade also reveals many things about the identity of the saber.
Here are the different types of munes that you may encounter :
While the Hira mune or Kaku-mune (flat mune) is mainly found on old blades, the Iori-mune or gyo no mune (mune having the form of a “roof”) is very present since the end of the Koto period. Two variants of Iori-mune exist, the mune Hikue (or Iori Hikushi) and the Takai (or Iori Takashi, more marked), but rather have a look below :
The Iori Takashi is often found in the Yamato tradition schools. The Iori Hikushi is more common in the Bizen tradition. Mitsu-mune or Shin no mune is quite similar to the Iori-mune but has three sides. It is relatively present and very characteristic of the blades of the Soshu tradition, as well as of the tantos of the Yamashiro tradition. Some famous blacksmiths of the Shinto period made this type of Mune. This was the case with Umetada Myoju and Echizen Yasutsugu (both from the Soshu tradition). The Maru-mune or So no mune (rounded) is rather rare (as for the Kaku-mune), not because it was particularly present on very old blades, but because it was very characteristic of the Ko-Aoe school, and of some very specific blacksmiths.