Viz Mask Kido

Actually no, he never directly uses kido with his mask on. He uses some kind of barrier technique that, while never directly stated, is implied to be the ability of his zanpakuto. This is given further traction in one of the recent manga chapters where he uses the same technique in conjunction withe the three other vizards all of which are using the powers of their shikai, implying again that the barriers are a part of his zanpakuto's abilities not kido.

"Technique class is also taken into account, and each class has separate cooldowns. So if, for example you used a tier V offensive reiryoku technique, you could then use a tier V offensive hand to hand technique and they would have separate cooldowns."

BM added this into the tech guide yesterday, but it definitely previously wasn't a thing before (to my knowledge). I've removed it so that ALL staff can contribute to the potential of this before it's added to the guide as an update. (I know it's important to don't jump the gun dude).

My reasoning as to why vizard can't use kidou with their mask on is as follows (c/p from PM for convenience):

Primarily, balancing. It balances the following:

1) They would have access to three Racial Perk Masteries at once, Mask Control, Kidou and Cero/Bala. The idea was to make one mastery available when putting the mask on, but removing the ability to use another. It was also meant to highlight the 'become less Shinigami and become more Hollow' lore approach, since Kidou is a mastery unique to Shini.

2) You could potentially use Shunko at the same time your Mask is on. As putting on your mask grants you an extra advantage, it was seen to be too overpowered in combination with it.

3) And as a personal note, I think that it was meant to give downsides to the Mask Control Mastery and that it wasn't a completely all-pros no-cons mastery.

Here's hoping this helps.

Even if they were locked out of Shunko as a drawback, it's still a technique that's bending mastery rules in order to be used. And that's generally a pretty big no-no. Sorry Marcian, don't think it's possible.