Much of the aiki-ken syllabus was developed by Morihei Ueshiba (植芝 盛平 Ueshiba Morihei, 1883–1969) at his dojo in Iwama, Japan, at the same time he developed aikido's staff training (called aiki-jō). It is well documented that Ueshiba studied several different styles of kenjutsu (Japanese swordsmanship), but the aiki-ken techniques are predominantly based upon the teachings of the Kashima Shintō-ryu.
Most of the practice of aiki-ken was ultimately systematized not by Ueshiba, but by Morihiro Saito (斉藤 守弘 Saitō Morihiro, 1928–2002), one of Ueshiba's most dedicated students and the person who took over the Iwama dojo after Ueshiba died. Hence the unofficial term "Iwama style" to refer to Saito's style of aikido, incorporating a significant amount of weapons training. In order to preserve the art and to teach an increasing number of students, Saito gathered the teachings of Ueshiba and presented the world with "aiki-ken". The first aiki-ken techniques were published in "Traditional Aikido", Vol I and II by Morihiro Saito, 1973. Before his death, Saito and his son Hitohiro Saito (斎藤 仁浩 Saitō Hitohiro, born 1957) revived and refined this art.
Note that the practice of aiki-ken is not pervasive. Some schools of aikido incorporate weapons training that is unrelated to aiki-ken, and others forego weapons training entirely.
Much of aiki-ken bears little similarity to other modern sword arts. Rather than learning to "fight" with swords, the primary purpose of aiki-ken is to magnify errors in one's aikido technique, and to give the student an opportunity to apply the principles of aikido in different situations. Aiki-ken is practiced using bokken (a wooden katana) and has a wide variety of techniques. Saito codified two sets of techniques, the first being seven suburi (solo cutting exercises), and the second being five partnered forms. Some dojo also practice jiyu-waza armed with bokken (freestyle technique, without a predetermined form of attack and response).
There are seven aiki-ken suburi, and are very simply named as follows:
The partnered forms practice of aiki-ken is called , meaning the crossing/meeting of swords. There are five kumitachi in Saito's aiki-ken curriculum. The kumitachi teach students how to alternately control the center line and move off it to avoid attacks and how to blend with an opponent's attacks, among other skills.
Improvisational variations on the kumitachi (called henka), which generally cause the kumitachi form to end early with one person taking advantage of an opening to strike or throw the other, are also taught.