Part of the beauty of judo and jujutsu is their ju-ishness. Because these arts are built on the principle of pliability, it means that whatever problem you are given, the answer lies not in what you can't do, but in what you can do! This is freeing and empowering and it gives us hope in any sort of difficulty.
Sure, the problem places restrictions upon you, but no problem can restrict you completely in every way. If there is somewhere you can't move, then move somewhere else. If there is somewhere you are not strong enough, then be strong in some other place or some other way!
Take kesagatame as a concrete example. We often approach groundwork from the perspective of trying to identify the hold-down and then apply the correct, known, named escape. We say (in a bad kung-fu movie accent), "Aha! I see your kesagatame is strong, but my uphill escape is stronger!" This is an okay way to get started playing with groundwork, but there is a problem - you have to know an answer or two to every problem that the other guy could pose. Otherwise, you rapidly reach some position or condition that you dont know the answer for and you get frustrated and lose hope and submit.
Look at the real problems that kesagatame presents...
- Your side of ribs are being compressed (probably painfully)
- Your back is being pressed flat against the ground, creating lots of contact surface and limiting your mobility.
- Your head is being controlled, and is probably being pulled out of alignment with your spine, weakening your muscles.
- One (maybe both) of your arms is being controlled tightly.
- It is hard to breathe - positional asphyxia is imminent.
- The opponent is hooked to you in an assymetric position, making it hard to lift or push him off.
- The opponent is sitting close to one side of your body, which makes it hard to move that way.
So, in the face of such daunting problems you might be tempted to submit just so that you stop the pain and breathlessness and lack of control. But check this out. Those are just about the only ways that he IS controlling you! He is leaving you several options, like...
- Bridge with your powerful leg muscles to lift your butt a little bit, then turn on your side facing them and press your sternum against them. This reduces or resolves several of the problems above, including 1,2,5, and 6.
- Fling your hips and legs away from the opponent, rotating at your held head/shoulder, then fling your hips back into the opponent. This will often tear some space in the hinge, reducing or resolving several of the problems above - 1,2,4,5
- Put your free hand on the back of the opponent's head/neck and bridge your butt as high as you can, piling weight into their neck and driving their face into the ground. This reduces or removes problems # 1,2,3,4,5,and 7.
- Put your free hand between their head and yours and push as you turn to your belly and get your knees under you. Voila - problems #1,2,3,4,5,6, and 7 solved.
We happen to call this sequence of actions "uphill escape" for convenience, but it is not "uphill escape" that the bottom man is thinking when he gets those problems piled on him. He is thinking, " can't breath...hurts... can't move... Let's see where I can move freely. Yep, I can move there. Yep I can move there too! Now it's not so bad and I can move here! Oh! where did he go?"
All of these actions have in common that they are motions in unresisted or minimally resisted directions.
It's not about what you can't do. You can never know if you are powerful enough to blast through any potential problem, but you can know for certain that you are powerful enough to act in ways that you are not resisted.