North-South Armbar and Some Options
From Brazilian Jiu-jitsu Techniques Wiki by My BJJ Blog
Boarder starts off on top of North-South. He keeps his weight on Nogi and uses his knees to help control Nogi's head. He controls Nogi's left arm with his right hand and grabs Nogi's right arm with his left.
The pic shows how Boarder grabs Nogi's arm. This is how the arm should be grabbed in the first photo above. He uses his whole arm to hook or grab the arm near its elbow. Also, Boarder secures the arm by gripping his own lapel or shoulder.
With the arm tight and secure, Boarder pulls up on the arm using his whole body, lifting Nogi's left shoulder off the mat in the process. Let's call this step B.
The same position, just showing a different angle of step B. When Boarder pulls up on the arm, he will step his left foot flat right next to Nogi's back. This should be tight and the foot should be planted below the shoulder blades. Boarder should lean forward, pushing on his hips, moreso than the picture shows. He should also use his head to control the wrist/hand of Nogi. When this step is tight, Boarder can make Nogi tap simply by applying pressure on Nogi's elbow by using his left leg and head on the arm.
Boarder starts the armbar movement by twisting/turning to the right. He repositions his right leg and plants it flat on the mat near Nogi's head.
Different angle of the last pic. Boarder is spinning into the armbar. He has to keep his hips low and tight, or the armbar will be loose.
Boarder falls back into the armbar. As he pulls back, he also pushes up on his hips, squeezes his knees together, and pushes down on his legs.
Different angle of the same picture above.
Different angle of the same picture above. Boarders left leg stays on Nogi's back. Armbar complete.
Let's go back to step B. Suppose that Boarder wasn't using his head to control Nogi's wrist/hand....
...so Nogi is able to avoid the armbar by bending his arm.
Boarder see this and takes advantage of the change in situation. He quickly uses his right hand to grab Nogi's left wrist.
Boarder then grabs his own wrist with his left hand.
To complete the Kimura, Boarder sits the right side of his hip down on the mat on or right next to Nogi.
With his hip down and base secure, Boarder then brings his right elbow down on the mat. By this time, Nogi should be tapping already. If not, boarder should just continue cranking the kimura until he gets the tap.
If Nogi is able to twist his arm out of the Kimura, Boarder will just need to slightly reposition his arms to go for the straight arm lock to get the tap.
Let's say that from Plan B, Nogi is able to once again bend his arm but in addition he grabs his other hand and holds on, making the kimura difficult.
Boarder will first step back with his left leg so that he is on both knees again. From this step, Boarder already has his grips to do the Kimura, but because Nogi is defending, Boarder cannot bring the arm out to finish the sub. So first, Boarder must reposition his left hand, the one that is around Nogi’s arm and is gripping his other wrist, so that he grabs his elbow instead.
Boarder steps across with his right leg. Before or as he does this, he should let go of his right hand grip on Nogi’s wrist, and grab his left elbow. All he has to do now is to sink his elbows down to the mat (adjusting his base as neccesary) to make Nogi tap to a crazy painful bicep squeeze.
