This is about the standard rolling back take from top of the half guard. All the instructions I have seen seem to start from a backstep. Is the backstep is necessary if I am alreday hooking his same side leg from the top of half guard.
as long as your knee is free I find it fine. If your opponent has your leg trapped in reverse half guard above the knee I find it a real problem.
GARRA - as long as your knee is free I find it fine. If your opponent has your leg trapped in reverse half guard above the knee I find it a real problem.
Well, yes, I agree. I wouldn't try a back step in the first place if my leg is trapped above the knee in half guard. Which is what led to my original question, why does everyone start rolling back take by doing a backstep first?
Because you have to roll diagonally across his body more towards the feet. How can you roll in that direction without back stepping first? How can you get your body pointed the right way without moving your outside halfguard (non hooking) leg out of the way?
is this from opponent in normal half guard youre talking about or deep half?
Can't comprehend how you could do it without back step to get oriented right.... unless you are talking about different position?
Is this what you're talking about?
http://www.youtube.com/watch?v=PFvdppqY5us
Not necessary to do the back-step but you need to be careful they don't take YOUR back in the process.
not necessary. I learned it first as a counter to the calf crusher from half guard: Armdrag from 1/2 guard and instead of taking the back grab the foot and sit back applying pressure. You roll through when he starts to sit back. Also, I've gotten the calf crusher on bigger guys when I try to roll and take their back but there isn't enough momentum.
The backstep is not necessary, but it is a good tool to help expose your opponent's hips to open him up for the rolling back attack.
Imagine you are on top in half guard, one leg is trapped, your opponent is flat on his back. Now you stay still, but imagine your opponent rotates in the direction of your TRAPPED leg 180 degrees so he is belly down. You are now on his back, and your trapped leg has become a hook, follow? Lets call this the "good" rotation, as it is the one we are looking for to expose our opponent's back.
Now reset back to regular half guard. This time, the opponent rotates towards you 180 degrees, in the direction of your FREE leg, so he is belly down. Are you on his back? No, far from it! You have some weird inside out hook thing with your right leg. Lets call this "bad" rotation as it hides your opponents back.
Now when do we get our opponent to give us the "good rotation" instead of the "bad"? Well, it certainly isn't from playing a regular half guard position, as a good player will try to sit up into you and dig an underhook, not face away. There are 3 main positions where "good" rotation may occur.
1. You backstep, opponent turns into you (note: because you've changed sides, turning to face you is now "good" rotation)
2. From regular half, you smash your trapped leg into a 3/4 mount. Opponent turns towards the half trapped side to shrimp out.
3. Certain deep half situations where your opponent goes for a sweep out the back door, or you sit over his head to end up in what is essentially a "backstepped" position.
Notice that all three of those situations have a rolling back attack option.
Vu hold yet ground. Good post bro 
What HoldYerGround said.
You CAN roll directly from a knee-cut type situation, but you have to roll sort of underneath yourself and/or do a lot of hip-escaping after the roll, and it generally becomes more reliant on speed, since you're at more of a risk of him taking your back in the process.
So, the back-step is not necessary, but IMO much better.
Thanks, guys. Very good info, especially HoldYerGround. I really appreciate the help.
A follow up question. I think it is generally better to hook the same side leg (ie, my right shin hooking behind his right knee). However I have also seen variations which the top guy hooking the bottom guy's opposite leg, especially when the move is executed from standing half guard or dela riva guard. Any comments?
Another related thought, it seems the move could be a good option when the bottom guy has reverse dela riva guard, as the top guy will be hooking the same side leg by default.