Whilst iaido is a modern term, the techniques and styles it usually encompasses came about with the introduction of the Shinogi-Zukuri katana that would be intimately connected with the samurai. Other sword types were also used during different eras, such as the longer tachi during the feudal period. Whilst the tachi was supposed to be used on horse back, the katana was more suitable for combat on foot. As Tokugawa Ieyasu became Shogun and united Japan, ushering in the Edo period (1600 – 1867), it became common for samurai to wear more relaxed clothes and wear their swords in their belts (obi).
One of the earlier references to the basic iai-techniques, drawing and cutting in the same motion (nukitsuke), comes from Tsukuhara Bokuden (1490-1570) from Kashima. Little is known of his style of swordsmanship, but he is claimed to have used a method called hitotsu tachi (one cut). Some of the earliest, still practiced, martial arts schools that include iai techniques are Tenshin Shoden Katori Shinto ryū, Tatsumi ryū, and Takenouchi ryū.
An important individual to iaido was Hayashizaki Jinsuke Shigenobu (1542-1621). His school, Shinmei Muso ryu, is a precursor to a number of styles of iaido, including: Musō Shinden ryū and Musō Jikiden Eishin ryū – two of the most widely practiced styles in Japan today.
In 1868 the control of Japan was transferred from the Shogun to the Emperor again, and in 1876 the samurai lost the right to carry their swords. This made it difficult for the old martial arts schools to survive in Japan, causing many koryū (schools predating 1868) to disappear. The new budo replaced the older styler, among others jūdō, developed by Jigoro Kano (1860-1938).
During the 1960s the All-Japanese Kendo Federation (Zen Nihon Kendo Renmei) developed their own official kata series, called ZNKR iaido or Seitei iai. These are based on a number of sword schools, including Musō Shinden ryū, Musō Jikiden Eishin ryū, and Hoki ryū.
Musō Shinden ryū
Nakayama Hakudo (1869-1958) founded Musō Shinden ryū in 1932. A practicioner of the Tanimura and Shimomura branches of Hasegawa Eishin ryu, he reorganised and modified kata from the latter when he developed the sword school. Musō Shinden ryū consists of three series of kata, called Shoden (初伝), Chūden (中伝) and Okuden (奥伝).
Shoden was developed by Hayashi Rokudayo Morimasa (1661-1732), the 9th grandmaster of Shinmei Musō ryū. He had previously practiced Shinkage ryū, under Omori Rokurosaemon Masamitsu, and based Shoden on this (Omori ryu).
Chūden was developed by the 7th grandmaster of Shinmei Musō ryū, Hasegawa Chikara no Suke Eishin. He is considered to have been essential in the adaption of iai-techniques for use with the katana, carrying it with the edge upwards in the belt. He developed Hasegawa Eishin ryū, which is the basis for the Chūden series of kata.
Following the 11th grandmaster, Oguro Motoemon Kiyokatsu (-1790), Shinmei Musō ryū divided in the two branches of Tanimura and Shimomura. A century later Oe Masamichi Shikei (1852-1927), from Tanimura branch, compiled the kata that now make up the “sister school” of Musō Jikiden Eishin ryū.
- Hayashizaki Jinsuke Shigenobu (1542-1621) [Shinmei Muso ryū]
- Tamiya Heibei Shigemasa
- Nagano Muraku Nyudo Kinrosai
- Momo Gumbei Mitsushige
- Arikawa Shozaemon Munetsugu
- Banno Danemon no Jo Nobusada
- Hasegawa Chikara no Suke Eishin (Hidenobu) [Eishin ryū]
- Arai Seitetsu Kiyonobu
- Hayashi Rokudayu Morimasa
- Hayashi Yasusada Masanobu (Seisho)
- Oguro Motoemon Kiyokatsu (-1790)
- Hayashi Masu no Jo Masamori
- Yoda Manzo Takakatsu
- Hayashi Yadayu Masayori
- Tanimura Kame no Jo Yorikatsu
- Goto Mogobei Masasuke
- Oe Masamichi Shikei (1852-1927) [Musō Jikiden Eishin ryū]
- Matsuyoshi Teisuke
- Yamakawa Kyuzo Yuki-O
- Shimomura Moichi
- Hosokawa Yoshimasa
- Nakayama Hakudo (1869-1958) [Musō Shinden ryū]