The question is what discipline would he be doing? I’d guess something practical that relies on utilizing the enemy’s movements against themselves so something like Judo or Hapkido?
Considering his low…
I’d take what I say here with some caution as I haven’t practiced in over four years but I could see Yamato feasibly using the majority of the techniques in Hapkido. The main body of techniques have emphasis on circular motion, whether it be how you move around your opponent, how you deflect their attack, or how badly you break a wrist.
A lot of the introductory stuff is linear but it does set the groundwork. If I recall correctly my first few months consisted of how to punch, how to use a palm strike (personally I prefer this as I haven’t almost broken my wrist with palm strikes), how to fall and roll to prevent injury, basic grappling, a few kicks (front, side, roundhouse), basic grabs, and the circular block.
I know I’m rubbish with describing things, but the motion used in the circular block becomes the core of several techniques so it’s important to know this if for some reason you’re seriously considering what I’m typing :V Scrap that, I re-read my attempted explanation and saw it creating confusion, so you’re better off looking for videos I guess.
Anyway, higher up leads to cresent kicks (along with the previous kicks being from a moving start), more grabs and counter-grabs, how to throw people by exploiting their momentum and centre of gravity, how to fight dirty on the ground (aka break everything you can get your hands on), pressure points, and eventually various ways to break joints to limit your opponent’s options. I never made it all the way to Black Belt, but I did here from some of them they they have sessions where they practiced techniques against weapons too.
I know I didn’t make a good job of explaining this, but a substantial amount of the higher techniques involve using circular motion to guide an opponent’s attack to place them in a disadvantageous position. Back when I was practicing it was fully feasible for me to redirect a punch to position myself to deliver an elbow to the throat while tripping them over. Turning a punch into a shoulder dislocate or an elbow break was also a technique that was taught, although admittedly I’ve pretty much forgotten how to perform that one :V