ironbuttmonkey | SUPER SENSING YOUR ROOMMATES DOING IT THROUGH THE WALL. ROUGH NIGHT FOR EVERYONE.

Originally, Sanageyama used the Tengantsu technique. It involved rapidly moving his eyes to take in his surroundings and the movement of his target, allowing him to read the preparatory movements of his opponent and predict their movements beforehand.

Extra eyes on the chest and back.
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During his initial fight with Ryuko, he also displays the ability to study the movements of his opponent and adjust his own accordingly; an example is breaking through the defense of someone who can block his attacks.

Initially but after a few seconds.

As badass as this was, it did have a glaring weakness.

M-my eyes! The goggles do nothing!

By cutting off a section of her uniform and directing the cloth to stick to all of his eyes, Ryuko blinded Sanageyama, completely nullifying his Tengatsu's ability. If he can't see, he can't read anything, leaving him completely vulnerable. Basically.

So with that said: what the hell is Shingantsu?

Shingantsu is an enhanced version of Tengantsu that Sanageyama received by having his eyes sewn shut. This was in part to prove he had the resolve to learn from his mistakes to Satsuki and regain his position amongst her ranks, but also to enhance his other senses and force himself not to rely upon his sight as he had before.

So they fight again, and Ryuko immediately opens with the same strategy she used to defeat him in round one. 1 2

It doesn't end very well for her. 1 2

Shingantsu functions in a similar manner to Tengantsu, except instead of relying upon one sense, it relies upon his remaining four, primarily his sense of smell and hearing. Although it does function in a similar manner to Tengantsu, allowing him to read and react to preparatory motions and movements to predict and counteract them, it also allows him to look even further into his opponent and get a general sense of their emotions and thoughts. 1 2 3 4 5

Basically, although he's blind in the traditional sense of lacking sight, this is a condition I like to call Anime Blindness™ in which it doesn't fucking matter whatsoever.

By taking in his surroundings through his senses, Sanageyama is fully aware of everything that is happening around him, to the point he can even predict what is going to happen. He knows you're going to throw something at him before you even do it, even if it's from behind. He can tell from your behavior if you're frustrated, scared, or happy, and use this information to predict your thought process and how your emotions are going to influence your movements, coupled with the way your body is moving.

Basically it's unrealistically broken in how vague it is.

SO. From his current canon point, the threads sewing his eyes shut have been removed. Essentially he now has both his TENGANTSU and SHINGANTSU.

His Mind's Eye is only capable of sensing shapes and positions, like the sonar that it is. Adding his eyes lets him see colors and light, so he can not only see screens but also see the colors and textures of objects, and more easily infer the position of objects behind other objects.

However! Despite how great it is having some kind of vague all seeing eye in your mind, it has it's weaknesses.

Firstly, if his opponent is too fast for Sanageyama to keep up with, he can't react. When he attempted to attack Nui, she simply slipped in beneath him, pulled out the thread holding his uniform together and ripped it apart, then kicked his ass.

Secondly, while not as big a deal as the first, if his opponent is stronger than him it'll be difficult for him to contend with them, strength vs strength(the reason it's not as big a deal as dealing with a faster opponent is if they aren't fast enough to block/hit him, he can simply outmaneuver them.) 1 2 3

Lastly, because of his enhanced senses, he reacts to things a lot harder than others might. As an example, when Satsuki offered him tea, he said he couldn't drink it because his enhanced sense of taste wouldn't be able to handle the heat. However, he deals with the sound based attacks generated by Jakazure's uniform just fine, which hurt the ears of everyone in the stands watching her fight with Ryuko, barring the two other members of the elite four. He also got caught in a sonic blast generated by her MK.II uniform at the culture festival later in the series, and didn't react to it beyond being scorched from the explosion it generated. He also handled the sound waves generated by the COVERS as well as the others did around him. 1 2 3

While I could speculate on this forever, it's probably just the mechanics of the world bending to whatever fits the narrative since that's how Trigger operates, so this probably isn't a reliable method of defeating him, but I figured it's worth noting.