The lbw law, taken one condition at a time

What the law is trying to prevent

The law exists because a batter standing in front of the stumps could otherwise defend them with his pads and never risk an edge. Without it, the safest technique available in the game would be to obstruct the line of the ball rather than to attempt to play it. Everything that looks fiddly about the wording follows from that single purpose, since the law has to separate obstruction from an honest attempt to bat.

That is why the conditions are cumulative rather than impressionistic, and why an umpire answers a chain of narrow questions instead of forming a general view. An appeal that feels overwhelming to a bowler often fails on one link in that chain, which is the usual source of the frustration that follows.

Where the ball pitched

The first question is where the ball bounced, because a delivery pitching outside the line of leg stump cannot produce a dismissal however plainly it was going on to hit. That exemption protects the batter from being trapped by a ball he could only reach by playing around his own body, which would make the angle punitive rather than skilful. A ball pitching outside off stump carries no such protection, so the whole off-side region remains available to a bowler willing to attack the front pad.

This asymmetry shapes how spinners operate, because bowling into the rough outside leg stump removes one of their dismissal routes entirely for the duration of a spell. It also explains why a bowler going round the wicket to a right-hander is often trying to keep the pitching point on the legal side of that line.

Where the ball struck the batter

The second condition concerns the point of impact, and the answer here depends on whether the batter was genuinely attempting to hit the ball. If a shot was offered, the impact must fall in line between the two sets of stumps for the appeal to survive that stage of the test. The corridor is defined by the stumps themselves rather than by the batter, so someone who strides a long way across is not sheltered simply by having moved.

Impact outside the line of off stump is the most common escape route, which is why batters push the front leg towards the ball instead of planting it behind. Height matters at the same moment, since a ball striking high on the pad has less room to descend onto the stumps and more chance of passing above them.

Whether it would have gone on to hit

The third question is predictive rather than observational, because the umpire must decide what a ball that was stopped would have done had it continued. That judgement combines the height at impact, the distance from the stumps and the amount of movement the ball was still carrying when it struck the pad. Distance is the variable most often underestimated, since a ball intercepted well forward has a long unseen path over which small errors of angle accumulate.

Movement compounds the problem, because a delivery deviating at the point of impact may or may not have continued deviating across the remaining distance. This is where honest observers most often disagree, and it is the part of the decision that technology was introduced to model rather than to observe.

The shot that was never played

A batter who makes no genuine attempt to hit the ball loses the protection normally offered by an impact outside the line of off stump. The reasoning is direct, since padding a ball away is exactly the obstruction the law was written to discourage and cannot sensibly be rewarded with a wider margin. What counts as a genuine attempt is the judgement least reducible to a rule, because a bat held near the line may or may not be trying to make contact.

Umpires tend to look at whether the bat was moving towards the ball rather than merely present, and whether the head and the weight travelled with it. The practical effect is that leaving on length is safe only when the ball is demonstrably missing the stumps, and dangerous the moment it is not.

Review, margin and the umpire's original call

Ball-tracking systems produce a single confident-looking trajectory, but the underlying prediction carries an error band that widens with the distance being extrapolated. The provision that leaves marginal decisions with the on-field umpire exists to acknowledge that band rather than to defend anybody's authority. It produces the outcome spectators find hardest to accept, where two near-identical images resolve differently because the original decisions were not the same.

That is a design choice rather than an oversight, and the alternative is to treat a model's marginal output as though it were a direct measurement. Reading the provision as a statement about uncertainty rather than about hierarchy removes most of the confusion that surrounds it.