This trains the principles of going with the direction of a grab to change, and of going above the head to protect yourself against a joint controlling grab. This drill should be usually practised continuously for at least 20 minutes so that the wrists visibly swell up. Wrist wringing develops the qi in the wrist area of the person being grabbed. It develops the sensitivity of the person grabbing, as they learn to differentiate between grabbing skin, tendons, bones, blood vessels, etc. It is more effective to grab bones or tendons than to simply wrap around the whole wrist, especially if the partner has a thick wrist. Do allow some sliding, though, or the drill cannot be completed.
1. Single grab. Partners stand facing each other in mabu. One partner takes the wrist of the other and turns and lifts it like playing with a sabre. In one direction you are trying to lift your partner's elbow, in the other direction you are trying to twist into the shoulder. The grabbed partner protects the wrist by acting like a sabre. That is, protect the wrist by doing a chuanzhang. Extend the arm, rotating it into the direction of the grab, and move your power up and towards your partner. Do not 'go into' your arms, but stay in your body, or you will be pulled around easily.
2. Double grab. The same, but grabbing with both hands. This is much stronger, so be careful not to put full power into the grab and twist. The grabbed partner still needs to be able to rotate the arm.
3. Double grab with stepping. One partner takes the other's wrist in two hands and steps across with a koubu then rolls to circle the arm fully around, like playing with a sabre. The grabbed partner goes along sideways with the circling to keep the arm safe, extending and putting energy into the grabbing partner. The grabbing partner rolls under the arms to complete the circle, continuing in the same direction.