This elbow trick is used for stepping close to the opponent and striking the straight elbow to the neck of the opponent, then swings it to the opponent's jaws.
To protect
Twist the body and step back to escape from the opponent.
To counter
Throw the right or the left knee to the opponent's rib. You can study this trick by sitting and pitch the left elbow on the table, the tip of the hand pointing to the right side, don't move the elbow then tip the arm up very strong to stand straight. So you will know more of this trick.