Ude-hijigi or Ude hishigi
(arm bracket or arm crush)
"This lock is attempted when both Tori and Uke are engaged
in tachi-waza. An opening for it's application can occur if Uke
carelessly stretches his right arm to his front. With your right
hand grasp Uke's right wrist from the inner side so that the thumb
side points towards his elbow. The inner side of his arm is kept
upper most (your hand must be over his wrist). Advance your left
foot a little and turn your body to the right so as to bring you
round to his right side. Pin Uke's right upper arm under your
left armpit.
Your
left under arm should be in close contact with Uke's elbow or
it's upper part and should pass underneath so that with your left
hand you can grasp your own right lower lapel. The role of your
right hand gripping your opponents right wrist is to push the
latter downwards in the reverse direction, forcing Uke to tilt
foreward on his toes. As you keep up the downwards preasure on
his right wrist Uke is unable to relax and severe pain is inflicted
on his elbow joint."