Yonkyo (Fourth Teaching)
四教
Pressure from the index-finger bone onto a nerve on the inner forearm. It works through a pain point rather than a joint lever — and does not work on everyone.
Quick Facts
⚠️ Common Mistakes
Common mistakes: squeezing the forearm with the fingers instead of pressing with the bone, hunting for the right spot by squeezing, and assuming the technique works on everyone — it does not.
💡 Key Tip
Do not hunt for the point with the fingers. The pressure comes from the bone at the base of the index finger and from body movement.
About
Yonkyo, the fourth teaching, is also called tekubi osae in Japanese, the forearm pin. It differs in principle from the three preceding techniques. Ikkyo, nikyo and sankyo all work through leverage on a joint, whereas yonkyo works through pressure on a nerve point: the defender grips the attacker's forearm with both hands so that the bone at the base of his index finger presses into the inner forearm roughly where the nerve runs. The pull then leads the arm down and forward much as in ikkyo. This is exactly why yonkyo is taught after the others — and it is also the least reliable of them. Sensitivity to pressure at this point varies markedly from person to person, and on some partners the technique does not work at all. Honest schools say so openly and teach yonkyo as a complement to ikkyo rather than as a solution of its own. It is practised standing and as a ground pin, in both omote and ura.