Utsuri which is seen as a straight line, regardless of the shape of hamon.

Bo-utsuri is found of many of the Osafune smiths' works after Oei era. Also found on Sue-Aoe blades.

Also sometimes referred to as sugu-utsuri 直映り (lit. 'straight utsuri').

See utsuri for more information.

Clove-shaped ashi.

The cutting edge of the kissaki. Also, the curvature of the kissaki. It can be described as rounded or not rounded.

Goban Kaji are the smiths who were summoned by Emperor Gotoba for his personal instruction and the research and development for perfection to the Japanese Sword. See more details here.

Imperial property. An item is referred to as Gyobutsu if it belongs to the Imperial Collection of objects which are either of aesthetic or historic value to Japan or to the Imperial family (supervised by the Imperial Household Agency). The most famous collections are the Shōsōin Gyobutsu (正倉院御物) in Nara and Higashiyama Gobunko Gyobutsu (東山御文庫御物) in Kyoto.

Also, from the Muromachi period onwards, the shoguns followed a similar system. Objects from their collections were also called Gyobutsu (e.g. objects once in the collection of Shogun Ashikaga Yoshimasa (1435-90) are called Higashiyama Gyobutsu (東山御物). The term Ryuuei Gyobutsu 抑営御物 refers to the collections of the Tokugawa Shoguns.

(Source: JAANUS)

This term is actively used in Kyōhō+Meibutsu+Chō to describe whereabouts of particular meitō.

Osaka Gyobutsu - collection of Toyotomi Hideyoshi (see NN-4-7-23)
Owari Gyobutsu - collection of Owari Tokugawa family
Gyobutsu - property of Tokugawa shogunate

See nagasa.

Uneven box shaped hamon. See also: hakoba.

A notch on the blade side. See machi.

Various activities, distinctive features of the steel seen inside the hamon and ji, created during the hardening process.

See hataraki in hamon and hataraki in jihada for an overview of different types of activity.

Blade without a shinogi.

Activity which looks like stray lines from hamon into the ji.

Activity in the hamon similar to kinsuji, but resembling lightning. Inazuma runs out from the hamon into the ji and then back into hamon. Kinsuji is found only inside the hamon. 

An example of inazuma can be seen here.

The Tokugawa Shogunate standardized the size of swords in Japan during the Edo period to what is commonly called jōsun length. For katana jōsun is 2 shaku 3 sun 5 bu (71.21cm), for tantō - 8 sun 5 bu (25.76cm).

Tantō longer than jōsun are called sunnobi-tantō 寸延び短刀, and less than jōsun sunzumari-tantō 寸詰まり短刀. There was no standard length for wakizashi, but those over 1 shaku 8 Sun (54.5 cm) are called ō-wakizashi 大脇指. Tachi 太刀 of more than 3 Shaku (90.9 cm) are referred to as ōdachi 大太刀, whereas tachi under 2 shaku (60.6 cm) are called Kodachi 小太刀.

Source

Rough polishing given by swordsmith to inspect for any flaws just after yaki-ire process.

Blades longer than 60 cm are called katana. They are worn thrust through the belt, with the cutting edge facing upward. The katana superseded tachi beginning in the Muromachi period. One distinctive style, produced in late Muromachi, is known as uchigatana. It as it's deeply curved in the upper part of the blade and is wielded with one hand.

Choji midare pattern with the peaks which resemble tadpoles.

It can be seen in the works of Osafune Mitsutada.

'Sword-shaped'. Shape of the nakagojiri with two straight lines coming to a point in the center at around 90 degree angle.

It is often seen among works of Masamune and his school, and Shinto swords made in Soshu tradition.

Lit. 'Chrysanthemum in the water'. This peculiar type of hamon made in Shinto times by smiths like Kawachi no kami Kunisuke and his followers.

The fan-shaped part of the blade above the yokote and the ko-shinogi. It may be whitened by polish. It's size is described as 'large' or 'small'.

The part of the shinogi that runs from the yokote to the tip in the kissaki.

Lit. 'Chestnut-shaped'. The rounded shape of nakagojiri.

It's the one of the most commonly seen shapes.

Lit. 'Famous thing'. In relation to Nihonto, meibutsu is:

1. a sword which is famous for its smith or owner(s) or most likely both.
2. a sword listed in Kyōhō Meibutsu Chō. This record was compiled by Honami Mitsutada (本阿弥光忠) at the order of the Tokugawa government in Kyoho era. It enlists famous blades of historical importance from late Heian to Yoshino period. Detailed descriptions of the blades from Meibutsu Cho can be found in Albert Yamanaka's Nihonto Newsletter.

Irregular pattern of hamon. All hamon except [suguba] are midareba.

Sub-types of midareba:

• ko-midare - small midare
• o-midare - large midare
• saka-midare - slanted midare

The notch dividing the blade from the tang on the mune side. See machi.