Setting up and Finishing the Arm Triangle From the Bottom: A BJJ Tutorial
The Arm Triangle
Setting up and catching an arm triangle from the bottom (guard position) is likely one of the first submissions you learn, but one of the last you master. There is definitely a trick to setting it up, and several tricks to the finish. This tutorial will offer some setups from very basic to moderately tricky, and a few different ways to complete the choke. Keep in mind that the back take and subsequent sweep are always viable options any time the head and arm choke doesn't work out. For more techniques you'll learn as a white belt, but work on for the next several decades, check out the BJJ Tutorial Encyclopedia.
Forearm Choke Setup
Here's one of the easiest ways to start working on the arm triangle from the bottom (or from anywhere, for that matter); when a "bully" starts to go for a forearm choke from inside your guard. My favorite way to apply this submission is to employ a little bit of guile and act like the choke is working, so my partner really commits to it, hopefully tripod-ing up to apply full body weight forward. It's easy enough to avoid being choked by this for real by simply extending your legs away, utilizing the power of your hips from closed guard, but you don't want to overdo this, as you're trying to "sell" the idea that your opponent can actually choke you. Feel free to make gagging sounds to amplify this.
When you feel your partner's full force coming forward into the "choke", it's important that your right arm (in the video) shoots straight up and then across your partner's back, grabbing their far armpit. This will engage your shoulder in the choke. Now simply pop their arm out of the way at the elbow and tricep area, landing it across your body on the other side of your head. From here, you need to be sure to bring your right ear in close to their shoulder, lest they pull their arm back and posture up in the closed guard. Finally, apply the choke by making a "rear naked choke" grip with your arms, settling in with your left arm behind your head.
Advanced Set up From Tall Posture
Second Variation - a Trickier Setup
In this second technique, Trey sits up into his partner after using the basic "prayer hands" posture break. Here, he gives forward energy into the head, almost like going for a hip bump sweep (without the arm across, much like if he were going for the hip bump to triangle set up.) As his partner pushes back down, Trey simply redirects the elbow up just a hair, while simultaneously dipping his head underneath the tricep (similar to a duckunder from the feet). From here, it's important that he "listens" with his right ear, so his partner can't have his arm back, while continuing to control the head, but deep enough to engage his shoulder. Trey opts for the "Gable grip" here for the finish.
Same Technique, One Motion
In this video, you can really see how Trey uses the energy of his partner pushing back in to redirect the arm across his body, while dipping his head to the side to "listen" again. For the submission itself, especially with the Gable grip, it's important to drive your head to the right in order to push your partner's arm across their neck, effectively sealing the choke on both sides. You can also opt for the more traditional bicep grip if that floats your boat.
An Alternate Finish
Sometimes the choke is really hard to finish from here, or your partner's neck is just too wide for you to be able to finish the arm triangle. While going to the back or sweeping are always options, the Ezekiel finish (the "arm in" version) is right there. Make sure your right arm is fed through deep enough so that you can grab your sleeve with your left arm, and then bring your left wrist across your partner's neck. An added detail shown here on the finish: make sure you move your head away to give yourself enough room to extend (as opposed to the arm triangle finishes above, where your head stays in tight.)
These setups are pretty sneaky (besides the very fundamental forearm choke option), but you can start using them more or less immediately. Keep in mind that with all the above techniques, you're very close to already taking their back, and if they resist the back take, you can often sweep your opponent fairly easily. As always, let us know what you think of the tutorial, and happy training!