I know it has been a long time since this thread was active, but I would like to put in my 2ยข for a second too. Keep in mind enemy types. Someone who is ate the mera mera no mi would aways win against a zombie, unless someone like blackbeard, akainu, or someone with kairoseki intervened. However, a swordsman who fights a zombie is in a completely different situation in ability match ups, and are more or less on an even playing field. I'd say that sword vs rokushiki is an even playing field type of match up, but I'd say that rokushiki vs zombie isn't. I'd say in that situation kaku would win, seeing as all of these different rokushiki techniques would allow him to basically force ryuuma to do whatever he wanted as far as strategy and tactics goes.