Guard Theory

Passing Foundational · Gi and no-gi

Passing half guard starts at the head

To pass half guard, flatten the bottom player's shoulders with the underhook and a crossface before working on your trapped leg, because a flat player can use neither a knee shield nor an underhook.

Position and problem

One of your legs is trapped between theirs, and the instinct is to work on it: pull it, kick it free, walk it out. While the bottom player is on their side with their head up, pulling on the leg mostly helps them. Their knee shield holds your chest away, or their arm slides under your armpit on the side of the trapped leg, and each tug on the leg brings you closer to a sweep or to giving up your back. What decides whether the leg leaves at all is the bottom player's head and shoulders, and the three bottom games commonly met there (the knee shield, the underhook and deep half guard) each depend on the bottom player's body being somewhere your upper body can take away.

Objective

Put the bottom player's shoulders flat on the mat with the underhook and a crossface, keep them there, and only then free your trapped leg.

Core concept

Half guard is passed at the shoulders, and the leg comes free last. Win the underhook on the side of your trapped leg, or wrap their arm with a whizzer when they get there first, and put a crossface across their jaw with your other arm so that your shoulder turns their face away from you. Between them, the two arms put both of their shoulder blades on the mat, and a flat player has lost the two things half guard runs on. The knee shield needs their hips turned onto one side so the shin can angle across you, and the underhook needs the shoulder on the underhook side off the mat so the arm has a body behind it. Once the shoulders are flat and your chest is heavy on theirs, your trapped leg is attached to someone who cannot follow it, and freeing it becomes a choice of route. Two routes are common. The knee slice turns the trapped knee out across their thigh and slides it free with the hips low; the backstep turns your hips away and steps the free leg over, pulling the trapped foot out from the other side. Deep half guard asks a different first question, because the bottom player is already underneath your hips rather than beside you, and many passers answer it by keeping their weight back over their own hips until they can take that position away.

Key mechanics

  1. Take the underhook on the side of your trapped leg before anything else. It is the same space the bottom player's best arm is reaching for, and whoever gets deeper there decides whether they come up or go flat.
  2. Crossface with the other arm, shoulder under their jaw, so their face turns away from you. A head turned away cannot lead the body up onto its side.
  3. When they win the underhook first, wrap it with a whizzer and drop your weight onto it. The whizzer keeps the arm from reaching your back and drives their shoulder toward the mat, which starts the flattening again.
  4. Against a knee shield, bring the shin down instead of climbing over it: turn it flat under your hip or work an elbow inside it. The shield only holds distance while their hips stay on their side.
  5. Against deep half guard, a common answer is to keep your weight back and your free leg wide, and to avoid reaching forward for the head. Deep half sweeps tend to work by tipping a passer who is leaning over the bottom player's body.
  6. Keep the chest heavy and the hips low once they are flat. A flat player fighting your weight is framing from their back, and a frame from the back holds less than a frame from the side.
  7. Free the leg only once the shoulders are flat, by the knee slice or the backstep. The route matters less than the timing, because either one tends to work against a flat player and both struggle against a player on their side.
  8. Keep the crossface and the underhook on while the leg comes out. Letting go of the upper body to use a hand on the leg gives them the moment they need to turn back onto their side.

Common errors

  • Working the trapped leg first while the bottom player is on their side, which feeds them the underhook and the sweep that follows it.
  • Taking a crossface without the underhook, which leaves the arm on the side of your trapped leg free to frame on your hip or slide under your armpit.
  • Climbing over a knee shield with the chest high, which rests your weight on the shin and lets it hold you away.
  • Freeing the leg and lifting the chest at the same time, so the bottom player turns in and recovers a knee between you.
  • Backstepping before the lock on your trapped foot has loosened, so the turn stalls halfway with your back toward them.

Safety

When you backstep or knee slice, a tight lock on your trapped foot turns the movement against your knee, so loosen the lock with the hips and the foot before turning, and as the bottom player let go of a lock that is being turned against instead of holding it. Flattening someone in half guard puts your shoulder against their jaw with your chest weight behind it, and while their head is turned away the neck twists with the pin. Drive the shoulder only as far as it takes to put their shoulders on the mat, then hold it there without adding more. If you are underneath and your jaw is being forced further than your shoulders can turn, tap or give up the position rather than straining against it.

Training progression

  1. Static: from top half guard, take the underhook on the side of your trapped leg and the crossface, and feel your partner's shoulders go flat before you touch the leg.
  2. Cooperative: partner holds a knee shield with light pressure. Bring the shin down under your hip, flatten them, then free the leg with the knee slice.
  3. Cooperative: the same start, freeing the leg with the backstep instead, with the crossface held on throughout.
  4. Underhook fight: both players start without grips and fight only for the underhook on the trapped leg's side, resetting when one of them is flat or up on their side.
  5. Constrained: the bottom player picks knee shield, underhook or deep half at the start of each round and may sweep; the top player scores only by reaching side control after flattening.
  6. Live rounds: after each half guard pass you try, recall which game the bottom player was playing and whether they were flat when your leg came free.

Written material cannot correct your positioning, feel your pressure or stop a submission in time. Everything here is intended to make training with a qualified coach more useful, never to replace it.

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