What half guard is
Half guard is a bottom position in which you hold one of your partner’s legs between yours while they are on top. It is the base of the half guard family in our guide to BJJ guards, and it is played in both the gi and no-gi. Your partner is working to free the trapped leg and pass. You are working to sweep, take the back, come up to your feet or get back to closed or open guard.
Grapplers used the position long before anyone built a game around it, mostly as a last defense against a pass. Roberto “Gordo” Correa is credited with turning it into an attacking guard in the early 1990s, after a knee injury, and the underhook was central to that change.
The underhook and the crossface
Most of half guard is decided by two things: whether you are on your side or flat on your back, and who controls the upper body. Your partner wants your back on the mat and their chest on yours. Their usual tools are a crossface and an underhook on your top arm. With both, they can settle their weight on you and limit your movement and your breathing.
Your answer starts with staying on your side, facing your partner. The underhook you want is on the side of the trapped leg: your top arm under their armpit. That is the same arm they are trying to underhook, so both of you are fighting for one position. When you cannot win it, keep that elbow tight to your body, inside your hip, so their arm has no gap to dig into.
Your bottom arm protects your head. Kept high, alongside your head, it makes it harder for their arm to slide across your face. Your legs stay locked around the trapped leg, tight enough that your partner cannot pull it free while you fight for the arms.
Knee shield, deep half and other variations
If your partner is heavy on your upper body and you cannot reach the underhook, a knee shield puts your top knee in front of their body to hold their weight off you, as our Z guard article explains. If they have already won the underhook, you can go underneath them into deep half guard.
Other variations work through the legs. In the lockdown, your legs lace around the trapped leg and stretch it. In half butterfly, a butterfly hook under the trapped thigh lets you lift your partner for sweeps. When they have nearly freed their knee and you hold only the foot, you are in quarter guard.
Sweeps and back takes from the underhook
With the underhook in place, the work is to get your head and shoulders out from under your partner’s chest, so their weight no longer pins you to the mat. The back take, the sweeps and the wrestle-up all start from there.
Grips
- UnderhookYour top arm under their arm and around their back, on the side of the trapped leg.
- Frame on the neckA forearm across their neck holds their upper body away when you have no underhook.
- Pants grip at the ankleThe grip that sets up the old school sweep.
Main attacks
- Back take
- Old school sweep
- Kimura grip back take
- Wrestle-up
- Deep half entry
Grips
- UnderhookYour top arm under their arm and across their back, with no jacket to hold.
- Frame on the neckA forearm across their neck holds their upper body away when you have no underhook.
- Ankle gripWithout pants to hold, your hand wraps the ankle itself for the old school sweep.
Main attacks
- Back take
- Old school sweep
- Kimura grip back take
- Wrestle-up
- Deep half entry
Distance
Half and knee shield
Your partner’s weight tells you which way to go. If they drive forward, sweeps that control a foot work well, because they cannot step that foot out to catch themselves. The old school sweep works this way. If they base out wide to stop a sweep, the back is often open instead.
The kimura grip, a figure-four lock on one of their arms, gives you a second route to the back. Even when they defend the shoulder lock, you can use the grip as a handle to bring your body behind them.
Expect your partner to fight the underhook. The usual counter is an overhook, also called a whizzer, on your underhooking arm, which stops you from slipping out to the back. They can also attack a D’Arce choke around your head and underhooking arm.
How partners pass half guard
Many passers control the upper body first and free the legs last. With a crossface and an underhook, or two underhooks, they flatten you. Then they free the trapped knee and finally the foot, finishing in side control or mount.
Another approach is to turn their hips to face your legs, a position often called reverse half guard, and free the leg from there. Frame against their hip as they turn, before their weight settles on you.
A passer can also catch one of your arms in a kimura grip and use it to pin you, or to move to side control while still holding the arm.
What a reviewer looks for in your half guard
On video, a reviewer looks at the first exchange on the upper body: who reached the underhook first, and whether the crossface landed before you turned onto your side. They check what you did when the underhook was lost, whether you changed to a knee shield or deep half or stayed flat, and how your partner’s knee came free when the guard was passed. In a roll review, a verified black belt points out each of these moments in a voiceover on your footage and in a written report.