- #42
As j0x pointed out, Ichigo knows blunt without any training, something that Isshin said only a full blood Quincy obtains naturally.
That's where your whole theory fail.
Knowing something without any training means that it is something inherent to you, something you knows since birth. A full blood quincy can use blut as easily as lifting an arm, as it was a part of his own body. It is not something he needs to learn at all, even without any education he should be able to inherently do it.
Ichigo never used blut in his past fight and he almost died I don't know how many time.
The reason is simple : He didn't know how to use blut.
Ichigo is a genius when it comes to learning. Let's me remind you that he always did what other people takes years to do in a matter of days or even hours. Seeing Kirge use blut in addition to the explanation of how the technique work by Urahara was enough for Ichigo to learn it at that time. That's right, he learned it, he didn't inherently know it.
Therefore Ichigo is not a pure blood quincy, add to that the fact that he cannot be a pure blood quincy because his father isn't one and the fact that surviving the holy selection do not means that you are a pure blood quincy but are recognised as being a quincy worth living by Bach as well as some other information that point towards it and the debate is pretty much done. Ichigo is not a full blood quincy.