25. Koryo and Choong-Jang target punches

The target punch originally comes from the karate kata Chinte.

Chinte's target punch. Source: Shotokan Sensei

Both Koryo (KTA) and Choong-Jang (ITF) make changes to this technique. Koryo's version is in riding stance and sets up the punch with a knifehand block. Choong-Jang's version is in back stance and changes the setup movement into a backhand downward strike.

Both versions are commonly interpreted as grabbing the back of the opponent's head and punching their face. The trouble with this is the risk of punching their forehead, breaking your fingers. Traditional forms usually aim punches at the rib or solar plexus level, and reserve the head for other strikes (backfist, knifehand, etc).

Knifehand blocks may be used to push out the face or neck. If you push out on the side of the opponent's face with the knifehand block in Koryo, this exposes the side of their head, a target safer to punch.

Source: PracticalKataBunkai

But what of Choong-Jang? Here we perform the downward strike with a stomp. This bizarre motion, to my knowledge, only appears in Choong-Jang.

Stomping motions can be used as knee strikes or as attacks to the opponent's leg, so it may be that the stomp is the primary attack, and the downward "strike" is just setting up the target punch. Stomping into a back stance is ineffective because the weight stays on our back leg, so I favor the knee strike interpretation.

However, we can also throw in a grappling application for the downward strike, since I don't think it works particularly well as a "strike". If you reach around the opponent's face and grab their jaw, you may use the circular motion as a head crank, setting them up for a strike to their neck.

Application for Choong-Jang's downward strike and target punch. Source: Martial Arts Guardian.

Combine with the knee strike to the lower back for greater effect.

Since the technique is open-handed, the intent may be to use the arc hand (since the thump is out) to get a chin lock instead. In the image below the outer thumb is used, but the effect is the same. This is safer for your fingers, as there is less chance of being bitten.

Source: Bunkai Jutsu

Finish with a punch to the side of the neck.