Cakes baked for JBW's birthday by Natalie Farnsworth. Note the special cake for John with 5 stripes on the black belt. Tasted even better than they look.
Grab the heel - attack the end of the lever. It is harder to negotiate with a bent leg than it is with a bent arm.
Find the sweet spot - you should go as deep as possible with your crotch on his leg, as you would his arm on an armbar. Your hips should be slightly above (toward his hip) so you have maximum leverage to drive your hips into his knee to hyperextend it.
Chase the knee - you should be facing his shin, instep and knee directly to apply a legbar. If the angle isn't right you must "chase the knee", orienting yourself around the leg until you are facing it directly. If he rolls, roll with him.
Against open guard foot on hips
Pummel your R arm under his L leg and catch his heel with your R elbow, Use posture to straighten his leg as much as possible. At the same time, push his R knee down with your L hand and step forward with your L foot, putting pressure with your L shin on the back of his R knee. Lift your L foot up, pointing your toes which should let you pull it out of any ankle grip, step over and clockwise, and sit down on his hips so his L leg is isolated. Fall off to the L, triangling your R ankle with your L knee, making it hard for him to kick your R leg off with his R foot. Apply the kneebar from here.
Against sitting guard
He is sitting up with his knees up and both feet flat on the floor. You are directly in front of him out of range. Your R foot should be forward and on a line directly between his legs. Step in fast with your R, turning side on, as you push his R shoulder with your R hand, back step outside his L foot with your L foot and pick up his L ankle with your L hand in an underhand grip (like a barbell curl). Complete the back step and sit on his hips, facing away, his L leg isolated. All the preceding are done as quickly and smoothly as possible. Fall to your L and finish as before.
From front control
You are in north/south, his forearms taking the weight, his knees up, feet on the floor. Take your fists far forward until they are about level with his knees. Jump up on your fists and leap frog over his arms, until you are sitting on his hips "in the armchair", each of your hands grabbing behind his knees, your elbows stuck behind your thighs so he cannot pull his legs back down. Lean back to create tension. Let go his R leg and step your R leg over it, isolating his L leg. Fall to the L and finish the legbar as before.
From side control
You have side control on his R with your R elbow next to his L ear and your R hand near his R hip (you could also have your R elbow beneath his L armpit). Switch base toward his feet. Threaten the mount, but encourage him to lift his R knee rather than his L by pushing it upward with your own R knee. You R hand goes over the top of his R ankle and grips it from inside, lifting it up. Your R foot goes under his R leg and over his L leg as if getting the mount on his L leg. Your R hand now switches to behind his R heel. "Dive" out across him with both hands, bringing your L knee onto hiss stomach like a knee ride, the R arm straightening his leg. Fall over the top of him onto your L side and kneebar his R leg. The L leg remains scrunched up. You get a bit tied up with this, but he gets tied up a lot worse.
From half guard top
He has half guard on your R leg and has a L underhook and has his legs triangled outside of yours. Get your L forearm atop his neck and work your way up so you have stiff arm control with your L hand on his L shoulder, your R on his R hip, your R knee on the floor, standing up on your L foot like a kneeride on the floor. Windshield wiper your R foot pivoting on the knee until your R foot is pointing at your L foot. Step over his torso, pivoting clockwise, with your L foot until you are facing away from him, come up on your R foot as well so you are sitting in the armchair with your legs either side of his L leg. Your L arm goes behind his L calf and your R arm around his R knee. Join your hands and squeeze his L leg and R knee together, together, exposing his R foot and as much of the R shin as possible. Hook your L knee over his R shin/ankle like a triangle, fall off to the L and apply the legbar to his R leg.
From quarter guard top
You have tried a knee slice pass with your R (inside) knee over his R leg, and your L foot off to the L side. He catches your ankle in a quarter guard with his legs triangled to the outside as above. Sit your R hipbone on top of his L hipbone so you can take a big back step with your L leg back behind both of you. (John got us to step our leg back and forth several times to ensure we had found the proper point of balance).
Now bring your L knee up behind both his R heel and use it to push both legs forward by squeezing your legs together as hard as possible. Grab his L shin and pull it toward you as you fall back, triangling your R ankle with the back of your L knee. Squeeze his L leg as hard as you can with the triangle. Wait for him to try to move and escape - immediately turn towards and kneebar that L leg.
(Excellent question asked by Simon Farnsworth) What if he manages to cross his R leg over the L to stop the kneebar?
If you are pulling hard enough on his L leg with your hands as you fall back this should tie his legs up tight and it will be hard for him to do this.
If he does manage it, not to worry. Grab his R foot and pull it up toward your face with both hands, as if doing an upright row. Catch the R foot behind your L elbow and trap it in your armpit. now reach for his L leg with your L and R hands and apply the kneebar. His trapped R leg actually makes the knee bar come on faster. There is a bit of a calf crush on his R leg and Achilles lock pressure on his L leg possible as well as the kneebar. Arguably this predicament is worse than what would have happened if he hadn't got his R leg free and crossed it over.
Single leg counter
He shoots for a high single on your R leg. Reach over his back with your R and grab his belt, back of his jacket, overhook of the left arm, neck tie, whatever you can get as a grip on his back. Hop in an anticlockwise circle until you L foot is outside his L foot and you are facing the same direction more or less. Reach down and grab his L ankle with your L hand. Take your L foot back a step as you initiate a forward roll over your L ear. Bring him with you as you come up to a sitting position with his L leg isolated. Finish the legbar from here as before.
Much of the more advanced legbar setup is designed to deal with problems before they occur. The biggest problem is that he will use his other leg to try and kick our top leg off and free his trapped leg. Any way we can somehow tie up that other leg and render it useless as a countering tool will pay off - the side control technique makes this impossible, but the triangling of his ankle in the half guard legbar and tying up his legs in the quarter guard technique are perfect examples of this. You could try the leg bar as soon as you turn away from him, but taking the time for the couple of extra steps to tie up his other leg leads to a superior outcome. We are delaying immediate gratification for a bigger payoff later, which obviously applies hugely to other aspects of life.
The legbar basics here are meant as a prelude and prerequisite for more advanced ashi garami (leg entanglement) techniques. You have a reasonable foundation in legbars before moving to more advanced leg attacks.
John did not go into fine points of controlling the foot etc. during the kneebar. For this, I like Dean Lister's approach.