This one strikes the player with his knee in the balls to gain the advantage to throw him on the ground. The counter is that immediately the player goes between with the knee to hurt him in the balls, that you take the right hand under the knee and throw him to the ground.
Locked in a grapple in which neither combatant has the initiative, as the 10th scholar, you take the advantage by driving your knee into your opponents groin. Notice that this is not a finishing technique in itself. You are doing this to hurt your opponent so that you can then throw them. Attack on the inside line where your opponent will be more open to impove your chances of success. The scholar pictured would be better using the left knee instead of the right.
Although the play describes a groin attack, you can just as effectively strike to the pelvis or solar plexus. Hitting your opponent successfully with a knee will jar their whole body, rendering them incapable of doing anything for a moment. Because you are holding them at close range, this means that they are usually open to a repeat attack. If your first knee hits home, you should be able to trap your opponent in a vicious cycle, getting an extra two or three in before running out of momentum. Being on the receiving end of a barrage of knee strikes is a memorably unpleasant experience.
There are two slight variations on how you can deliver your attack. For both variants, you need to be at extremely close range.
First and simplest is to raise the knee straight up and into the target. As the knee rises up, push your hip forward. Grab your opponent tightly and pull them down onto it. There is the sensation of leaping into your opponent. This is the attack as pictured. If you have a little more distance to make up, you can also grab your opponent by the shoulders, pulling them forward and down, while driving the knee into the solar plexus.
A second variant is from a low grip, raise your knee to horizontal while keeping your hip back as far as possible. When in position, drive your knee straight forward while pulling your opponent onto it. This will smash through the front of the pelvic bone, creating what is called an open book pelvic fracture. Your opponent will collapse to the ground in great pain and unable to walk.
The right circumstances to effectively use a knee attack are quite infrequent, but due to the fact that it is such a short movement, knees are difficult to counter. You need to keep your weight low and make the initial defence with your thigh. Rotate your hips inward, using the inside of your front thigh to push the knee offline. This will not only save you a lot of pain, but will give you the time needed to get your hand there.
Scoop under the inside of the knee. The player in the picture would be using their right hand to do this. Lift the thigh up, while pulling down with the other hand. Your opponent will twist and fall on their back to your outside. You can see the principles of this throw being used by