There is a story of Ueshiba being questioned about sen and asked whether aikido was not go no sen, completely offensive. Ueshiba blew up and stated “After all these years, you fellows haven’t figured any of this out yet! Don’t you realize there’s only one sen.” Ueshiba felt it was not right to divide sen up. Although there is no attack in aikido and the art is supposed to be purely defensive it, in its outward form, appears to be go no sen. However, if you are always responding, your movements will become short and choppy. The idea is to invite or draw out movement from uke. If you wait for someone to grab you, it’s already too late. You are not grabbed you cause someone to grab you. On the spiritual level you must always move before uke causing uke to attack in a certain way. Wherefore, in aikido, there is only one sen. Aikido is a manifestation of defensive go no sen combined with sensen no sen, initiative on a spiritual level. Together they manifest themselves as tai no sen.