Tameshigiri (試し斬) is a targeted cutting with a sword test. During tameshigiri a swordsman skill is testing these days. Different materials are used to test. Mostly rice straw (wara), top layer of tatami mats (goza), bamboo and much more.
A trick and a little presentation of how American Ki-Society aikido looks like and goes so far with Koichi Kashiwaya Sensei.