This should be a training video for little kids who are learning good sumo technique. Sokokurai has to use his entire skill set against the much larger Kaisei, starting with a great tachiai. He puts his hand under Kaisei’s chin, lifting him up so he can slide into the hidari-yotsu (left hand under, right hand over) grip. It’s hard to see because it’s on the far side, but Sokokurai uses a very close overhand grip with his right arm so he can clamp down on Kaisei’s left arm with his elbow and prevent Kaisei from securing his own underhand grip on that side. This works for a while, but once Kaisei gets his own hidari-yotsu it’s pure defensive mode for Sokokurai as he has to strain to stay in at the edge. This is where your core-strength training pays off. But even then he throws a little offense with an attempt at a right-footed outside leg trip, to no avail. His low stance pays dividends and he works Kaisei back to the center of the dohyo, to the delight of the crowd. Switching tactics, he releases his grip with his right hand, pulls his right hip back, and fights to try and break Kaisei’s left-hand grip. He locks up Kaisei’s left arm while moving steadily forward, and when Kaisei frees his left arm Sokokurai uses that instant to slide his right hand under and secure the morozashi (both hands under) grip. By now he’s used the distraction of the hand fighting to work Kaisei right to the edge, and it’s an easy task to use his superior low position to walk his opponent out for the yorikiri win. Solid stuff.