Andrew Smith is a 3rd-degree BJJ black belt based out of Richmond, VA (Revolution BJJ). He runs BJJ Path, a video tutorial website.
About the 50/50 Position
Once you start getting more familiar with 50/50 position, some options start to open up that seemed impossible before. Here, we'll take a look at taking the back directly, the now-classic armbar finish, and a rolling calf-slicer.
Option 1: Straight to the Back
As pointed out previously, the main idea for more than half of the techniques you can execute from 50/50 is to get your trapped (right) leg across to their opposite hip. This is easier said than done, so start by creating some distance between your partner's upper body and yours. A left-side stiff-arm does the trick. Next, hip out so that your right knee goes to the ground. If necessary, you can use your free right hand to help open your partner's knees up (you don't need much space here).
Now, keeping your right instep flush with your partner's left hip, hip out to move past their right knee (this is now going to be the main way they block you from going around to their back). Essentially, you're trying to create an arm-drag position, with your right hand on your partner's far collar, and your left hand on their sleeve. Just drag the arm across, take a temporary double underhooks back control, and secure your position as normal.
Option 2: The Armbar
Make sure you understand the mechanics of the basic back-take maneuver and get good at it. That way, you can just view this armbar option as something that's on the way to your primary objective. There aren't a ton of new movements involved. If your partner stops you from going around to their back by grabbing your collar with their left hand, this facilitates things.
Lie back so that their arm straightens out, but keep that same collar grip you had before; you don't want to get too far away from your partner's shoulder during this final transition. From here, it's just a straight armbar with your partner's leg caught in the middle. JT Torres finished Caio Terra with such an attack, and Keenan Cornelius was well known for using this finish at brown belt. The good news for you is that it's a natural consequence of your partner attempting to stop the back take.
Option 3: Rolling Calf-Slicer
This is arguably the flashiest of the three techniques presented here, and it's likely to be the one you use against a partner who is knowledgeable enough in 50/50 not to let you bring your leg across at all. Still, start with the "knee down" motion like before, but exaggerate it greatly, sliding your right knee underneath your partner's right leg. Hug your partner's right hip with your left arm, and then dive your head under your partner's leg, where your knee is heading. As you roll forward, you'll end up in a calf slicer if your partner doesn't straighten their leg (make sure you know your gym's etiquette before going for any leg attacks!). If your partner straightens, you have a back-take opportunity. Huge credit goes to Jake MacKenzie for demonstrating this move years ago at Revolution BJJ.
As early as 1997, I started using 50/50 as a leglock attack position. It became obvious that the position wasn't ideal for attacking if your skill level and understanding of the position wasn't superior to your partner's knowledge (think: Ryan Hall, one of the best in the world at the position). However, during the mid-2000s, there was a resurgence in popularity due to some folks having success at higher levels in competition with the position. This extended to the gi, but I personally had very little success in 50/50 in the gi until after 2010, when I started understanding how to disengage properly. This key concept allowed me to start experimenting with more and more options, and now I have a much bigger wheelhouse to draw upon.
In time, your own body of techniques will grow as well, although it's bound to begin with one or two moves and often end in frustration. The good news is that you're going to end up there often, whether you want to or not, so you'll have plenty of opportunities to improve!
© 2016 Andrew Smith