One of the most versatile and powerful weapons of Okinawan karate is the seiken (proper fist). To make a proper fist, start by extending all four fingers and pressing them tightly together.
Curl your fingers so that the tip of each finger touches its base. Continue to curl your hand, clenching the tips of your fingers tightly into your palm. Between strikes you may slightly relax your fist but be careful not to let the little finger come loose. Be sure to squeeze the fist tight again upon impact.
Fold your thumb down across the middle of your index finger and middle finger, as shown in the illustration. Keep your thumb curled tightly in this position to keep it from being hurt.
It’s very important to keep your wrist straight to extend the right angle formed between the front and top of your fist. This will enable you to transmit the maximum amount of force on impact.
The strong knuckles of the index finger and the middle finger form the striking area of the seiken. Be careful not to strike with the weaker knuckles of the ring finger or little finger.