So some of you are claiming that a fraction of chakra could repel a focus point of a lot of chakra??? My point is that the contact point between Kaiten and Chidori is where both body would put out chakra, but Kaiten is a fraction of the whole chakra (all the chakra have to spread out for the spin to work) and Chidori is concentrate with a lot more chakra in compare to that point of Kaiten's chakra. Yes that sounded weird but really I just don't think the spin would be fast enough to be able to "spread" that chidori damage over a large area. Remember lee's speed without weight? That's the kind of speed of Chidori, if not more, that would hit the Kaiten Chakra shield. Chidori will pentrated but some of its power should be cancel out, then the rest of the remaining "Kaiten chakra shield" would continue to spin and "catch up". All of this is just my guess though ....