In the late 1950s the Kendo Federeation invited classical iai expert swordsmen to form a commission to investigate courses of action. The result was a selection and adoption of seven iai kata. This list was later revised to ten kata by a later comission. These kata formed the basis of the Zen Nihon Kendo Renmei Seitei Gata. These ten kata form the basis of kendo based iai.
Further advancement is made within classical ryu.
Examples are the Muso Jikiden Eishin Ryu and the Muso Shinden Ryu. These two ryu are splits of the same branch and remain quite probably the most practiced ryu of iaido. These were the first to allow the public to join their ranks and participate as outsiders. The Seitei Gata have three opening positions. Seiza is used for the first three and is considered a non-combative position.