Half guard in BJJ is the position where you are on the bottom holding only one of your opponent's legs between yours. Played badly, it is the last stop before getting passed. Played well, with the underhook and your body turned on its side, it is one of the most dangerous guards for sweeps.
It is often taught as a fallback guard, the one you end up in when closed guard breaks. That is the wrong way to see it. Many black belts choose it on purpose because it gives direct access to the legs and back of the person on top.
Low half guard vs high half guard
Low half guard means your head is on the mat and you dig underneath your opponent. That is the game of the underhook, sweeps from underneath and escapes to the back. High half guard is played with your torso up and one hand controlling the collar or sleeve. It is closer to the logic of an open guard.
Beginners should start with low half guard. It comes down to one simple rule: never stay flat on your back.
There is also deep half guard, where you get completely under the opponent's leg. It is brutal, but it takes good balance and hip mobility that few people have in their first year. Save it for later.
The underhook is the key to the whole position
The underhook is your arm going under your opponent's armpit, on the same side as the leg you are trapping. As long as you have it, you can get on your side and attack. The moment you lose it, your opponent flattens you with their head and shoulder, the crossface, and you spend the rest of the round defending.
In practice:
- Your shoulder goes under their armpit, not under their chest.
- Your head stays glued to their side, never exposed toward the mat.
- Your bottom arm blocks their hip or grabs their pants to stop them from climbing.
- Your legs squeeze their leg in a lockdown or a simple triangle, with the top knee tight.
The underhook battle is won in the first second. If your partner already has the crossface, do not force the arm. Get back on your side with a bridge first, then slide the hand in.
Three half guard sweeps to know
The old school sweep
With the underhook, you turn on your side and reach for the ankle of their free leg with your bottom hand. Drive with your head and pull the ankle toward you. They fall to the side. It is the oldest sweep in the book and it still works, especially on people who lean their weight forward.
Taking the back
Same start, but the opponent defends by moving their hips back. Use the space to slip your head out behind them, then climb onto their back. It is often the best payoff, because back control scores more than a sweep and opens the choke.
Scissor sweep from high half guard
In high half guard you hold the collar and sleeve. Your top knee acts as a shield against their belly. Pull the sleeve toward you while pushing the trapped leg with your bottom leg. It looks a lot like the scissor sweep from closed guard, with one leg fewer.
From the top: how to pass half guard
On top, the principle flips. You need to flatten your opponent onto their back and take the underhook away.
- Win the crossface: your forearm goes under their chin and your hand reaches for their far shoulder. Their head faces away from you.
- Take the underhook on their free side yourself, or control their hip.
- Put weight through your chest. It goes into the top of their torso, not through your knees.
- Free the trapped leg, either by pushing it out with your free foot or by backing the hip out in small steps.
The classic beginner mistake on top is yanking the leg out with both hands while sitting bolt upright. You give space and they recover guard. The pass happens with the chest, and the leg comes out last. All the passing families are covered in our article on guard passing.
Once the leg is free, hold side control for three seconds before thinking about mount. Plenty of passers lose the position because they move on too fast.
Submissions you should not forget
Half guard is not only about sweeps. From the bottom, if your opponent posts a hand on the mat to stabilize, the kimura is right there. On top, a passer with the crossface can also look for an arm triangle when the bottom player pushes with their arm the wrong way.
What judoka recognize in half guard
For a judoka, half guard looks like having a leg trapped in ne-waza. As long as it is caught, the hold-down does not count. If it gets trapped during an osaekomi, the referee calls toketa. In judo, time on the ground is short and you try to free the leg to move into tate-shiho-gatame or a side pin. In BJJ you have all the time in the world, and so does the person underneath. That is why judoka often underestimate this guard at first. For an overview of the Brazilian side, see our Brazilian jiu-jitsu page.
A tip for your next rolls
Spend a whole session starting every roll from bottom half guard, with one instruction: never end up flat on your back. You will lose a lot at first. After three or four sessions you will feel when the underhook is won and when it is not, and that feeling is worth more than any sweep learned by heart.