Niten Ichi Ryu kenjutsu was founded by the legendary Japanese swordsman, Miyamoto Musashi, who was born in 1587. In his thirties, after having won 60 duels, Musashi realized that swordsmanship should not only be about winning. The purpose of practicing swordsmanship is to learn to accept that reality is constantly changing and to achieve a strong spiritual balance that cannot be disturbed by even the most threatening situation.

Niten Ichi ryu techniques are economical, without flashy or exaggerated movements. Targeting is precise, and the distance and timing is tight and without wasted movement. Niten Ichi Ryu consists of the following sets of techniques: Itto seiho (single sword), kodachi seiho (short sword), nito seiho (two swords), bojutsu (staff techniques), juttejutsu (a forked iron truncheon that can be used for trapping a blade) and jujutsu (unarmed combat).

Niten Ichi Ryu has been practiced at Aikiken from the beginning of 2001. In February 2005 Iwami Toshio Gensho, the 11th soke of Niten Ichi Ryu, gave Kai Koskinen the title of Monka, which means a person who is inside the gates.