Techniques · Strikes
The cross
The rear straight: the hip and the rear foot turning the whole body behind the punch.
Where it stands
| Technique | Teacher kept | In the student | Own runs |
|---|---|---|---|
| cross | training or prepared | distill7-245.8M26 October 2026 | 0 |
The cross was scripted from my spec in the five punches work: the right arm shoots out with the fist turning over, the chest turns left, the lead foot steps in and the rear heel comes up. It was the last of the five punches to land.
On 17 October, with the jab as a teacher for everything else, four punches reached the heavy bag and the cross stopped 9–12 cm short (run by run). To reach, the hips have to drive forward about 19 cm in 0.16 s. Extra presses and a reward for the hips made it reach, but a wider test found it 0 for 12: it only worked when it borrowed the momentum of a big rock in the stance’s rhythm. Then the aim point went inside the target, the target came a little closer, and the reward was graded instead of hit-or-miss (reward shaping). The cross landed 5 of 6 on the bag, but still 0 of 6 in the air.
The speed work found the real cause. The elbow never straightened past 37–44°, even when the policy was made to ask for a straight arm: its servo couldn’t get there in time. I allowed a stronger, less damped elbow, and a reward for the rear shoulder keeping up (the kinetic chain broke there) landed the air cross for the first time: 5 of 6 at 4.4 m/s.
On the higher guard the air cross was 3–6 of 12 in every checkpoint, and when I took the fast elbows away again it fell 3–14 cm short before retraining. The base, guard18-124.5M, lands 3 of 12 in the air. In the distillation distill2 lost it (0 of 12) and distill4 won the 3 back with more cross presses. The kept student, distill7-245.8M, lands 1 of 12 in the air. What’s next is the same as ever: the cross’s reach in the air, on the original elbows.
What I think, as a coach
When it kept stalling, I treated it like a student who keeps missing: “The target should be a little bit closer. And also whether it’s considered a hit or not, let’s not make it so binary. You get more reward the closer you are to the target.” Then: “Lower the bars.”
I also asked: “Why does it always take a step back?” The reference never does.
It was the punch I singled out when I asked for a more professional fighter. Later I turned the other way on speed: the fast elbows were unrealistic, so the cross has to find its reach on a normal arm.
Every attempt
It has only been trained together with other techniques so far, never on its own.
Shared training
Runs that trained it together with other techniques: a base model, a retrain onto a new stance, a distillation into the student. Their whole cost is counted once, in the shared figure above, not split.