User blog comment:Godisme/Everything But The Rain Op. 2 "The Rudiments"/@comment-2048489-20130307055311

Let me say a few things about Ouetsu's take on Ichigo.

Ok, so he said that Ichigo's different because he never had an asauchi to begin with, yet he has his Zanpakuto. Why is this important? Because according to his ideology, there CANNOT be a Shinigami with a Zanpakuto THAT NEVER PICKED UP AN ASAUCHI AND BONDED WITH IT. In other words, Ichigo is an impossible case. He has a Zanpakuto, yes, but its different because it does not use the same base template (the asauchi) as all the rest.

So how come this translates to Ouetsu not fixing his Bankai? Quite simply, he CAN'T. That's my take. He explained that "this method wouldn't work for Ichigo". Because Zangetsu is not an asauchi-based Zanpakuto, I'm guessing Ouetsu, in addition to seeing how important it is for Ichigo to know more about himself, simply has no idea how to fix Tensa Zangetsu. It's like asking someone to fix a machine the likes of which he has never laid eyes upon before; he'd be groping in the dark trying to do it. Ouetsu built the asauchi, while Ichigo somehow pulled Zangetsu out of himself without any help. Balling together what Ouetsu said earlier, the asauchi is the skeleton of most Shinigami's Zanpakuto, which they flesh out (give abilities) with the color of their own soul (don't know how else to put it :P). But since Ichigo just went and created Zangetsu, it simply HAS to be different, because Ichigo unknowingly used some other forging method to create Zangetsu, and thus forever making it different.

...actually that could send me off into another tangential theory concerning Quincy Spirit Weapon creation and using the resulting weapon as a Zanpakuto's base template instead of the Asauchi, but I won't go into detail.

On a side note, this might explain why Ichigo's Bankai couldn't be stolen; since all normal Shinigami use an asauchi as their Zanpakuto's base template, it would be natural for them to all be the same on a fundamental level, like DNA. And like how scientists calibrate pesticides, antibiotics, etc. to target certain strands of DNA these days, the Vandenreich could have somehow isolated the part of the Zanpakuto that was the Bankai and stolen it. Speculation all around here, but you have to admit it's quite probable, since Ichigo is the sole case of "didn't use an asauchi", which as Ouetsu tells us is a really big difference, enough to once again put him in a category all by himself.