It isn't a mode, nothing ever states that.
Zoro used 3 attacks in 1035 and in two of them, Onigiri & Dragon Damnation, you see the smoke cloud around all of his swords and "KoH Santoryu" being termed.
In Bird Dance, you don't see the smoke cloud nor the nomenclature. Just CoC being infused in Sandai alone.
That's 100% not a coincidence lmao, no matter how much you deny it.
There's your proof, how much more are you going to deny?