Beats all of them except Zaraki, Hitsugaya and Yamamoto
How could he beat Shunsui and Jushiro but not Toshiro and Kenpachi? And what about the other captains how does he beat their Bankai? Like Shinji? Seriously please dont just throw out names he couldn't beat without explaining because that makes now sense.
Kenpachi is the most overrated captain. Beats everyone based on brute strength, which doesn't really help his case vs Zoro anyway as he has plenty of comparable strength feats. Almost 0 skill feats however. Shunsui and Jushiro however were both the strongest captains not counting Head Captain Yammamoto as he trained them himself. They both fought him as well.
So what I'm asking is how exactly Kenpachi is capable of beating someone of Zoro's skill level but they aren't? If were being serious here, Kenpachi should be the one he is most likely to beat.