@thatguythere03 Page 20 looks vaguely like he headbutted the incoming punch, which is a thing that can happen in bareknuckle and lightly gloved rulesets-
- and it comes right after the line 'use your head!' Furthermore a few of the blocks can be interpreted as attempts to attack the fist or finger. And it looks a bit like Shuya collapsed holding his arm.
The other thing that the pose on the last page could be reacting to is indeed a liver shot: the most stereotypically 'full-contact karate' means of doing that would be either their front kick/round kick hybrid popularized by Ryu Narushima in Kyokushin and Katsunori Kukuno in MMA, the 'mikazuki geri/crescent kick' (https://www.youtube.com/watch?v=O04efC42gpw), or a simple shovel hook of the same type favored by boxers. Neither motion actually seemed to
happen in this chapter, but maybe we'll get a flashback 'it was too fast to see' kind of thing in 36.