In order to get a tight arm drag, or indeed to open up the arms for an underhook, using an “inside grip”, whereby your palm is facing outwards.

To perform the arm drag, reach your left hand deep up into your opponent’s armpit (using a thumbless grip) and reach your right hand around their back, grabbing their hip bone.

Stepping in, make sure your hips are tight to your opp, and that you’ve a knee either side of their leg.

While these photos are separate to illustrate the point, in reality you’ll do the two moves simulaneously. Continue to pull your opponent in tight to you with the arm drag. If done correctly, he should begin to lose balance and trip over your knee (Although it’s not necessary to have the knee pinching as tight as some other throws)

This technique really relies on killing space with the drag. Once you start the drag you’re constantly pulling your opponent over his near leg and into you.