Learn ko-uchi-gari, the minor inner reap in judo: kuzushi, heel and timing. Beginner-friendly and honest, with breakfalls and a supervised partner.
The honest answer: ko-uchi-gari is a quick, short throw that looks like a small thing and still forces decisions in randori. You sweep your partner's heel from the inside to front-outside while you push him backward with your upper body. The German Judo Federation includes ko-uchi-gari in the basic programme up to 4th kyu and assigns it to 5th kyu, together with more coordinatively demanding techniques such as harai-goshi and uchi-mata [1].
That is an honest hint: even the "small" throw is not trivial. It needs timing, a stable stance and a feel for when Uke puts his weight on the heel. Expect it to take clearly longer than with your first hip throw until the reap really lands. That is a practical rule of thumb, not a study.
In competition ko-uchi-gari is a throw like any other. If Uke lands on his back with speed and control, that is an ippon. If he lands only on the side and the shoulder axis turns past 90 degrees, clearly beyond a pure side position, it is a waza-ari; a pure side landing is a yuko [2]. With small throws in particular you learn how many gradations lie between "nothing" and "ippon".
Walk with Uke in rhythm, hands on sleeve and lapel. Observe which leg he stands on and whether his heel is loaded. Milestone: you correctly call which foot your partner is currently carrying weight on.
With pull and push you move Uke so that his weight shifts onto the heel of the standing leg. Without this balance break the reap is cosmetics. Studies with children suggest that uchi-komi with a preceding kuzushi cue helps with pulling and pushing actions [3]. That is a transfer from a study on o-soto-gari, which found no differences between practice types. Milestone: Uke feels the push onto the heel without you yanking on the arms.
Without a partner you practise the foot movement: sole from the inside against an imaginary heel, short pull forward and outward, standing leg bent, upper body upright. Milestone: 10 clean repetitions per side without tipping sideways.
With a partner you practise push and reap in one flowing motion without throwing. The foot lands, the hands push. Milestone: in 8 of 10 attempts the sole meets the heel and Uke has to react.
With your coach's approval you throw for the first time. The pulling hand accompanies Uke to the landing. In competition an ippon requires speed, force, landing on the back and controlled landing [2]. As a beginner control comes first. Milestone: Uke lands on his back, chin to chest, hands slapping.
Your attack targets your partner's leg, so you carry special responsibility here. In a Japanese school insurance database of 1,000 ACL cases from different sports, 99% of the judo ACL injuries were contact injuries [5]. In a further analysis of 2,142 adolescents with cruciate ligament rupture, the rate was highest in girls in 11th grade at about 19.5 per 1,000 athlete-years [6]. For training this means: controlled reap, never to the knee, never jerky, always with an accompanying pulling hand. Being thrown is also the most common injury mechanism in judo [4]. You only throw with a partner who can do ukemi, on tatami and under supervision. This guide explains and motivates, it does not replace supervised training.
Do not sweep to throw, sweep to ask: how does Uke react? Many step back, and exactly then your next attack opens. The small throw is often the question that the big throws answer.
When you later practise combinations (see our guide on combinations), ko-uchi-gari is often the bait followed by a second throw. That is practical knowledge, not a study. So train from the start to stay upright and balanced after the sweep, so you can continue seamlessly.
It belongs to the basic programme of the German Judo Federation and is assigned to 5th kyu [1]. It is small, but coordinatively more demanding than o-uchi-gari.
In o-uchi-gari you reap the whole leg from the inside to back-outside. In ko-uchi-gari you aim briefly at the heel and the weight that rests on it. Both work with backward kuzushi.
No. The rules penalise grabbing the legs with shido, as well as hooking a leg without an immediate attack [2]. Ko-uchi-gari is allowed when you attack with it as a technique.
That is individual. The foot movement often sits after a few sessions; the timing in randori needs clearly more time and repetitions. That is a practical rule of thumb, not a study.
O-soto-gari: The Major Outer Reap, a Classic That Demands Breakfalls