Learn kata-gatame in judo: enclosing uke's head and arm, base, holding-time rules and the safety limit at the neck. With milestones for intermediate judoka.
The honest answer: kata-gatame is a pin in which you enclose your partner's (uke's) head and one arm together and hold him on his back on the mat. The German Judo Federation (DJB) assigns it to the extended programme of pins, the material for 3rd to 1st kyu [1]. That is why it is classed as intermediate: the principle looks simple, but the hold touches the neck and head and demands care.
The rules make an important statement. A pin around the head and neck alone, without controlling at least one of uke's arms, is stopped ("Mate!") [2]. Kata-gatame includes exactly that arm. This is not hair-splitting but the rule the hold is built around.
The holding times are as for any pin: 20 seconds for ippon, 10 to 19 seconds for waza-ari, 5 to 9 seconds for yuko [2]. How long it takes you to get a safe hold depends on your base in kesa-gatame and yoko-shiho-gatame. Expect several sessions before you can hold it against resistance (practical estimate, not a study).
Uke lies on his back, you sit at his shoulder, chest to his chest. Legs wide, one leg back. Milestone: you hold the side position calmly for 10 seconds.
Grip uke's near arm and guide it upward until it lies next to his own head. Your head closes the space between his arm and his head. Milestone: uke's arm stays next to his head without you having to yank.
Both arms wrap around uke's head and his trapped arm. You clasp your hands. The pressure comes from your shoulders and body weight, not from pulling on the neck. Milestone: uke's breathing stays free and he reports no pressure on the throat.
The weight lies on uke's shoulder and upper body, the hips stay low. The legs stay wide so that you do not tip over. Milestone: you stay stable when uke pushes sideways.
If uke pulls the arm out, you switch without losing control into kesa-gatame or yoko-shiho-gatame. The holding time then keeps running until ippon, "Toketa!" or "Mate!" [2]. Milestone: you hold 20 seconds and switch cleanly once.
The line is clear here: kata-gatame is a pin, not a choke. Your pressure acts on the shoulder and upper body, never on the neck. Practise it slowly, without jerky pulling, and let uke tap at any time. The rules recognise tapping twice with hand or foot, or calling "Maitta", as submission [2]. At the first tap you let go.
The DJB itself says that children and young people should learn pins of the extended programme early, while chokes are put back [1]. Kata-gatame is one of the pins, but its closeness to the neck is a reason to practise it only under supervision. In the review of judo injuries the knee, shoulder and fingers are the most frequent injury sites [3]. Restraint is also appropriate when you first practise this.
This guide explains and motivates; it does not replace supervised training.
Start with the arm, not the head: once uke's arm lies securely next to the head, the rest almost closes by itself. Control the arm first, then clasp your hands. That keeps your partner's neck free of pressure and gives you the grip picture the rules require [2].
How to fit it into your week: practise twice a week for five minutes at the end of training. Hold twice ten seconds with a partner who resists only lightly, then swap roles. Stop the exercise as soon as anyone reports pressure at the neck. This is practical experience, not a study.
In the DJB programme kata-gatame is listed among the pins of the extended programme [1]. Because head and neck are involved, you make sure the pressure lies on the shoulder and not on the neck. If in doubt, your instructor clarifies the exact execution.
The rules say that a pin around the head and neck alone, without controlling at least one arm, is not allowed and leads to a stop [2]. When you enclose uke's arm, you comply with that requirement.
The DJB lists kata-gatame in the extended programme, so roughly from 3rd kyu [1]. Before that you learn kesa-gatame, yoko-shiho-gatame, kami-shiho-gatame and tate-shiho-gatame [1]. This is a guideline; your club may differ.
20 seconds for ippon, 10 to 19 seconds for waza-ari and 5 to 9 seconds for yuko, counted from "Osaekomi!" [2]. Uke must have his back on the mat.
Tate-shiho-gatame: How to Hold the Mounted Pin in Judo