›Ukenagashi‹ lets Uke slip , that is, his attacking sword. The technique is explicitly found three times in Seitei-Iai’s kata, conceivably also in other places. Here is a film with a few Bokken experiments from a awesome Iai Jutsu school (Mugai Ryu). What us interest is the two-handed execution of a kamae. The upper hand is held very loosely and allows the Uke to pick up (and slide off) the sword strike. The sensei attaches great importance to wielding the sword for defense with a safety reserve. A strong opponent’s blow should not go through.