>>280367734shinigami push their reiatsu into fake-hollows that are molded into the form of a sword (asauchi) but Ichigo was *born* with the hollow power to manifest, and the shinigami reiatsu, so he didn't *need* a proper asauchi, he had previously made his own.
That made it kind of shitty and weak.
However, being a quincy, he also had those powers present, but because he was a shinigami, he has an inner world and his powers are manifested as actual entities. This let his quincy side (old man zangetsu) interact with his opposite, the hollow/shinigami side (white).
After ichigo got his REAL asauchi, and he understood his powers, it meant they could become one true zanpakuto spirit. That spirit is still a mix of hollow, shinigami, and quincy.
So "True Zangetsu" is the zangetsu which can move around in those spaces. He can shift more shinigami (his normal side) or more hollow (horn of salvation) and he can use his quincy powers (blut) though he's not trained in them, so they're by far the weakest and he doesn't use them much.
>ywach acting retarded around itHe thought, because Ichigo was using the *base* zangetsu, that it wasn't the future he saw.
However, the way Ichigo fights in his bankai form, he's *sheathing* his shinigami zangetsu within his hollow zangetsu (the one that turned white and "woke up)
What Ywach did, when he was attacked the last time, was break just the outside, because the arrow weakened him just enough that he made a mistake guessing what future he needed to pull into the present timeline, because the future with just shikai ichigo seemed impossible to him.