Lesson Part 2 of 3 -- Marcelo explains three varieties of Hook-Sweep from Butterfly-Guard: If you are playing from bottom position and your opponent takes Half-Mount with an Under-Hook (or underhook plus some variant form of near-side elbow control; e.g. "Over/Under" Clinch, a.k.a 50/50-Clinch, Front/Side Head-Lock, Cross-Face & Under-Hook, et al.) don't let your opponent keep the Positional Control and possibly Pressure-Pass through (stall, break, and clear) with their technique and resting weight against your "Flat(-tened) Half-Guard." You must expend energy to improve your positioning and expand your offensive options, opportunities, and potential observables; otherwise, your opponent (if well-trained in jiu-jitsu themselves) may have the technical dominance and leverage to score points with a pin against you from Cross/Sides (Knee-Mount, Side-Mount, ) or even finish/endanger you with a chained submission attack (e.g. Near-Side Arm-Bar, Far-Side Arm-Bar, etc.). Construct a "Frame" with your arms to ward off your opponent's control over your near-side elbow (i.e. Marcelo's right-arm). Freedom of this particular joint will allow you to turn up onto your literal side, and maintain a lateral recumbent posture to pummel back your Under-Hook for a hip-escape transition into the "Half" and/or eventually "Full/Seated/Sitting/Upright," Butterfly-Guard. If your opponent is wearing a Gi, you can grip the material behind your opponent for extra control, or you may even have enough tempo to feed the bottom skirt-tail of their jacket's lapel around and seize it with your under-hooking hand. Next, find a way to gain control over your opponent's elbow opposite of your Under-Hook; ideally, you are looking for a hold that will prevent your opponent from readily posting on the mat against your momentum when you apply a turning/lifting Butterfly "Hook-Sweep." If your opponent is lurching forward while stooped at the waist and kneeling with both legs contacting the ground, you might be able to simply turn your opponent's upper body like a wheel until they lose their base and succumb to a sweep. If your opponent is keeping their center of mass low, you will need to pull them onto your primary butterfly hook as you fall back and raise your opponent up off the mat while turning them over with your "Over/Under" Control. However, if your opponent applies a counter-post and rectifies their own base against your initial sweep attempt by stepping outward with their free leg, you will need to apply a continuation to your attack and modify your sweep with a combination; work your bottom-leg (your auxiliary Butterfly or Half-Guard Hook, opposite to your elevating leg) so that you can coil your foot into inside space and deliver a kick to your opponent's posting leg. Use your upper body control to pull and stretch your opponent out along the axis of rotation with a fulcrum placed about their struck knee and the sole of your kicking foot. By stretching your opponent you are decreasing their rotational inertia and increasing the effect of your applied momenta; consequentially, you are also pulling their own center of mass toward their center-line reducing counter-torque and increasing the moment of inertia of your applied torque. This particular variation of the Butterfly Hook-Sweep is classified as a "Short" Hook-Sweep; as opposed to a regular/defaulted ("Long") Hook-Sweep or simply, "Hook-Sweep." If you surprise your opponent well with this technique, you may wind up in position primed and poised to solidify (top) Side-Control. However, depending upon whether or not you your opponent senses their demise and prepares a follow-up to your successful reversal, you might wind up inside their Half-, Open-, or Full-Guard(s).