With knowledge or without knowledge? Because if Shishio has full intel on Kenshin's ougi like Enishi did I bet he would win, and if he doesn't while Kenshin does I bet it's likely to flow the exact same way as their second battle because it'd be easier to find a timing to use the Amakakeru Ryu no Hirameki than Kenshin's pre-resolve hax self that was injured.