Actually, this might become clear when the anime comes up, but there's a moment in the Asura double page against Kaido, where it looks like Kaido is giving a few hits on Zoro and the Zoro shadows are blocking his hits, right before the final hit.
The lower right panel, there's a few shockwaves on the blades, like there were hits getting clashed really fast. I could be wrong, but it looks like it. And there's also the fact that Kaido has his arms raised with Club as if he was doing strikes against him.