Bunkai or the application is as follows.

KURURUNFA (Part 3)

http://www.geocities.com/sanzinsoo/kururunfa3.html

PHOTO No.51: Assume the opponent throw a right middle punch. You
receive it with right middle block.

PHOTO No.52: You grab your opponentfs wrist in your right hand,
and twist it counterclockwise.

PHOTO No.53: At the same time, you turn to right 180 degrees so
that you can put the opponentfs arm on your left shoulder. The
opponent is behind you.

PHOTO No.53: Your left shoulder is a fulcrum. The opponentfs right
arm is a lever. You pull the opponentfs forearm downward. Making
use of leverage, you can give him pain.

PHOTO No.54: While you do this armbreak technique, you make a rear
elbow strike with your left elbow to his solar plexus.


Sanzinsoo