Choku-zuki

Choku-zuki (直突き) translates literally to 'direct thrust.'

Karate

In karate and its variants, choku-zuki is the term used for 'straight punch.'

The chamber, or preparatory position, of choku-zuki is with the striking hand retracted to the hip or ribs, in a fist, with the palm facing up. The punch travels in a linear path directly toward the target, with the elbow behind the fist, tracing the fist's path. The hand remains palm up until the last two inches of the punch, when it rotates to face down. Ideally, the beginning of the fist's rotation coincides with the initial contact with the target. The elbow remains on the bottom of the arm. Permitting it to rotate to the side or upward exposes it to injury from either self-inflicted hyperextension, or from a stiff block by the opponent.

Contact is made with knuckles of the fore-fist.

A straight punch executed from a front stance (zenkutsu-dachi) is called gyaku-zuki (reverse punch) if the advanced leg and fist are on opposite sides, or oi-zuki (lunge punch) if the leg and fist are on the same side.

Aikidō

In aikidō, choku-zuki (as described under karate, above) is a basic attack from which throwing and pinning skills are taught. However, because in most aikidō schools it is the only punch from which defensive techniques are taught, there is no need to differentiate it from any other punch. Thus, it is shortened and simply called tsuki.

However, choku-zuki is still used in aikidō, and refers to a specific technique with the jō (staff). With the student standing in hidari katate-gamae, the weapon is lifted to the right hand, which slides to the bottom end of the weapon. The student shuffle steps forward (tsugi-ashi) and the right hand pushes the weapon for the strike, allowing it to slide in the left hand, and coming to rest with the left hand gripping the jō one third the distance from the bottom end. More simply, picture striking a billiard ball with a cue stick, except both hands grip the jō with palms down, and thumbs forward.

This technique is also executed from chūdan-gamae.