Ushiro-geri in karate: the heel kick backwards, looking over the shoulder, balance and why turning away can cost you a point in WKF kumite.
The honest answer: ushiro-geri is a heel kick backwards that fails not on power but on vision, balance and rotation. The leg stays close to the standing leg, and the heel is the striking surface [1]. The name says it: "ushiro" means back, "geri" means kick. You turn the upper body, look over your shoulder and kick where you last saw the opponent.
That is delicate because you briefly lose sight of him. The WKF rules make two clear statements. First, a score must show "awareness of the opponent": anyone who turns away after a technique risks the score not being awarded [2]. Second, a technique is invalid if you turn your back to the opponent after the technique (a sign of lack of awareness) [2]. A clean ushiro-geri therefore turns in and out again without permanently losing the opponent from your field of view.
The reward: a jodan kick (to the head) is rated ippon (3 points) in kumite, a chudan kick (to the trunk) waza-ari (2 points) [2]. That sounds tempting, but it is also why the kick makes sense only for well-prepared karateka. The injury side is honest: in Japanese university tournaments, 164 of 713 medical interventions concerned the legs [3], and a review of kicks in combat sports notes that impact forces are enough to cause injuries up to fractures [4].
How long does it take? Count in months until you hit on a stable standing leg while looking over the shoulder. That is experience, not a study.
Without a kick, you turn the head backwards from standing and fix a point. The head leads, the body follows. Milestone: you can look over your shoulder 10 times in a row without losing balance.
On the ball of one foot you turn a little way in, the heel of the standing leg pointing the other way. The knee stays soft. Milestone: you hold the rotation position calmly for 3 seconds without wobbling.
The kicking knee comes close to the body, then the heel pushes backwards, led by the hip. The leg stays close to the standing leg [1]. Milestone: the heel points back when you kick and not sideways.
The partner holds the pad at mid height. You hit only with the heel. First slowly, then with kime. Milestone: 10 kicks per side in which the pad is hit centrally and you look forward again immediately afterwards.
Only now do you combine the kick with a step or a feint. In kumite, knowing the "awareness of the opponent" criterion helps you [2]. Milestone: after the kick you turn back into fighting stance and keep the opponent in view.
This guide explains and motivates; it does not replace supervised training or a coach.
Add a short "gaze check" before each kick: in training, deliberately look over your shoulder before you turn. Anyone who automates the gaze direction loses the opponent less often and hits more reliably. That is experience, not a study.
A kick backwards with the heel in which the leg stays close to the standing leg [1]. You look over your shoulder and kick where the opponent was last.
That depends on target height: a jodan kick gives ippon (3 points), a chudan kick waza-ari (2 points) [2]. A prerequisite is, among others, "awareness of the opponent" [2].
Because you turn away and hold balance on one leg. Anyone who turns his back to the opponent after the technique risks an invalid score [2].
Less than for high head kicks, but hip and calf must cooperate. You build mobility over weeks. That is experience, not a study.
The movement yes, as shadow work. You practise the kick on a target with an experienced partner and pad.
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