We had a ground fighting thread in the Shaolin forum. Songshan Shaolin has a body of ground skills called
ditanggong, not too dissimilar to street BJJ, with the objective of quick joint destruction or positional escape to get back to one's feet. Think, in ancient times, on a battlefield. You're rolling on the ground and another dude running by sticks you with a spear, or the guy you're tangled with guts you. The goal is never to stay on the ground as in sportive BJJ. There are some BJJ guys who make the mistake of training sportive BJJ so much they think it's street safe. Then they get the old GNP because they weren't focused on defending punches, which aren't allowed in sport.