LBW Explained: The Rules, Ball-Tracking and Umpire's Call

The ball thuds into the pad, eleven fielders go up together, and the umpire has a second or two to decide. Was it in line? Would it have hit? Did it touch the bat first? Then comes the review, the replay, the ball-tracking graphic, and quite often the words umpire's call, which leave half the stadium happy and the other half furious.

Leg before wicket, or LBW, sounds complicated, but the law that governs it is really a checklist. If every box is ticked, it's out. If even one isn't, it's not out. Learn the boxes and the drama makes a lot more sense.

The LBW checklist

LBW is covered by Law 36 of the Laws of Cricket, which are written and maintained by the MCC. For the batter to be out, all of these must be true:

1. It is a legal delivery. You can't be out LBW off a no-ball.
2. The ball did not pitch outside leg stump. It must pitch in line between the two sets of stumps, or on the off side. A full toss that never pitches passes this test automatically.
3. It did not hit the bat first. If the ball touches the bat, or a glove holding the bat, before the pad, it's not out LBW. If bat and pad are hit at the same moment, the law treats it as bat first.
4. The impact is in line. The ball must hit the batter, usually the pad, but any part of the body counts, in line between wicket and wicket. There is one exception, covered below.
5. The ball would have gone on to hit the stumps. The umpire judges where it would have gone if the batter had not been in the way.
6. The fielding side appeals. Umpires don't give anyone out unless asked, which is why bowlers shout.

Off side and leg side depend on the batter's stance. The off side is the side the batter faces when taking guard, and the leg side is the side behind their legs. For a left-hander, everything flips compared with a right-hander.

The tricky bits: outside leg, outside off, and no shot

The two zones either side of the stumps are treated very differently, and this is where most confusion comes from.

Outside leg stump is protected. If the ball pitches outside leg, it's not out, however straight it then turns. If the impact is outside leg, it's also not out. The reason is old and practical: batters can't easily protect their legs from balls angled in from that side, and the law doesn't want bowlers simply aiming at the pads.

Outside off stump depends on what the batter did. A ball can pitch outside off and still be LBW, as long as the other conditions are met. The impact, though, is where the exception comes in:

• If the batter made a genuine attempt to play the ball with the bat, an impact outside off stump is not out.
• If the batter made no genuine attempt, for example padding up or shouldering arms, an impact outside off can still be out, as long as the ball would have hit the stumps.

This is the no-shot rule. It exists to stop batters from simply kicking away every ball outside off with their pads. Picture an off-spinner bowling to a right-hander. The ball lands outside off, the batter thrusts his front pad forward with his bat tucked behind it, and the ball spins back towards middle stump. No shot, so the fact that the impact was outside off doesn't save him.

Judging whether a shot was genuine is the umpire's call in the everyday sense. A bat held well away from the ball, purely for show, may not be accepted as a real attempt.

Would it have hit the stumps?

This is the part that asks the umpire to see the future. They have to consider the line of the ball, how much it was turning or swinging, how high it was bouncing, and how far it still had to travel. A ball that hits the pad just in front of the stumps leaves little room for doubt. A ball that hits the batter far down the pitch, after a big stride forward, leaves a lot.

Height matters as much as line. A short ball striking the thigh may be heading over the stumps, especially on a bouncy pitch. That's why umpires are often cautious when the batter is struck high or a long way forward.

How DRS checks an LBW

Under the Decision Review System, a team can ask the third umpire to look again at an on-field decision. For LBW, the third umpire works through the same checklist, roughly in this order:

• No-ball check on the bowler's front foot.
• Bat or pad first. Replays, sound-based edge detection and, where available, heat-based cameras look for an inside edge.
• Ball-tracking. A system using several high-speed cameras records the ball's path up to the impact and then projects the rest of its path. The graphic shows three results: where it pitched, where it struck the batter, and whether it would have hit the stumps.

The pitching result is shown as in line, outside off or outside leg. The impact and wickets results can also come back as umpire's call.

Umpire's call, and why the on-field decision matters

Ball-tracking measures the real path up to impact, but everything after that is a projection, and projections carry some uncertainty. Rather than pretend the technology is perfect, DRS keeps a margin around the edges where the on-field decision stands.

Here's how it works for the wickets check:

• If the umpire said out, the decision is overturned only if tracking shows the ball missing the stumps completely. If it is shown clipping, it stays out.
• If the umpire said not out, the decision is overturned only if a large enough part of the ball is shown hitting within a zone on the stumps. A ball just clipping the outside of leg stump or brushing the bails stays not out.

The impact check works the same way for balls hitting the pad right on the edge of the in-line zone. The ICC has adjusted the size of these zones over the years, so its current playing conditions are the official source for the exact definitions.

So the same delivery, tracked to clip the top of off stump, can be out in one match and not out in another, depending only on what the on-field umpire said first. It feels unfair, but it is deliberate. Umpire's call gives the benefit of the doubt to the person who saw it live, and saves overturns for clear errors.

Under ICC playing conditions for international matches, a review that ends in umpire's call is not counted as a lost review. The number of reviews allowed, and whether DRS is used at all, varies by format and tournament, so check the event's playing conditions.

What to watch on the next big LBW appeal

• First, where did it pitch? Outside leg ends the conversation.
• Second, was there a shot? If not, an impact outside off is still live.
• Third, was there an edge? Look for a deflection or listen for the sound.
• Fourth, how far down the pitch was the batter, and how high was the impact? Both make would it hit harder to judge.
• On a review, watch the wickets graphic and remember the original call. Clipping stays with the umpire.

The one thing to remember: LBW is out only if every condition is met, and DRS exists to fix clear mistakes, not to second-guess the close ones.