This Kon Muay is the important main Movement to defence against the fist (a hand with the fingers clenched in the palm (as for hitting))
By pressing against the top of the chest or the abdomen.
The attacker(red) walks in and throws the left fist to the defensives face.
The defensive holds the both hands up to guard ones face, while thrusting with the left leg to the top of the chest or the abdomen.
If the attacker throws the right fist. Do the same as above in the opposite directions .