Iaido emcompasses hundreds of styles of swordsmanship, all of which subscribe to non-combative aims and purposes. The term emerged from the general trend to replace the suffix -jutsu ( 術 ?) with -dō ( 道 ?) in Japanese martial arts in order to emphasize a philosophical or spiritual aspects of practice. The term 'iaido' approximately translates into English as "the way of mental presence and immediate reaction", and was popularized by Nakayama Hakudo. Last character, 道 is generally translated into English as the way. The secondary emphasis is on drawing the sword and responding to the sudden attack as quickly as possible (合).
Thus the primary emphasis in 'iai' is on the psychological state of being present (居). The origin of the first two characters, iai ( 居合 ?), is believed to come from saying Tsune ni ite, kyu ni awasu ( 常に居て、急に合わす ?), that can be roughly translated as “being constantly (prepared), match/meet (the opposition) immediately”. The term 'iaido' appear in 1932 and consists of the kanji characters 居合道. Late Haruna Matsuo sensei (1925-2002) demonstrating Muso Jikiden Eishin Ryu kata Ukenagashi
It is this emphasis of on combative techniques and strategies of swordsmanship beginning with the sword in the saya that designates Muso Jikiden Eishin-ryu as a system of iaijutsu. However, it should be understood that iaijutsu, as taught within our lineage of Muso Jikiden Eishin-ryu, does not stand in isolation from kenjutsu (the techniques of swordsmanship that are employed after the sword has been drawn), but is rather a component of a broad range of sword methods. In fact, it is often said that the life of iai lies in nukitsuke, the act of simultaneous drawing and cutting with the sword. One of the oldest extant koryu, or classical schools of Japanese martial arts, it is a system of strategies and methods of face-to-face combat, beginning with the sword in the saya. Seito Muso Jikiden Eishin-ryu Iai-Heiho (iaijutsu) is an authentic tradition of Japanese swordsmanship, with origins in the techniques of Hayashizaki Jinsuke Shigenobu, who established the teachings that would become Muso Jikiden Eishin-ryu (or simply Eishin-ryu) in the closing years of the Sengoku Jidai of 16th Century feudal Japan. This is a significant purpose in the continuation of the study of the centuries old traditions of iaijutsu and kenjutsu in our modern era and indeed the underlying mission of the Jikishin-Kai International. It is hoped that these qualities come to permeate every aspect of one's daily life, quietly exerting a positive influence on others, and as such, contributing to the gradual, but exponential, improvement of our communities and the progression of society at large. These qualities may, in turn, lead to the development of confidence, dignity and compassion. This can lead to the development of heightened concentration and a calm and relaxed mind, enabling a practitioner to more effectively deal with stressful situations. They can include the development of correct posture, physical alignment and coordinated breathing through sophisticated, precise movement and the awareness of the physical body. The qualities described above can result in a wide range of benefits for the committed practitioner. Iaijutsu and kenjutsu training train in kata that reenacts historic combative scenarios that resulted in death, creating an intensity of spirit, seriousness and focus found in few other arts. Iaijutsu is swift and precise, yet graceful its flow lending to an aesthetic quality with significant appeal. Iaijutsu waza and kenjutsu kata demand exacting precision and refinement, requiring in turn, a tremendous degree of concentration and discipline. Classical swordsmanship may be considered the apex of Japanese martial arts, and has directly or indirectly influenced a wide range of classical and modern bujutsu and budo.