Question One - Was this a Fair Delivery?
It is easy to overlook this question, but if the answer to it is 'no', the umpire can call a no ball and not bother to ask himself anything else. If the bowler was within his ground5 when he released the ball and had his arm straight throughout, chances are that it was a fair delivery, and the umpire can move on to question two.
Question Two - Would the Ball Have Gone on to Hit the Wicket if the Batsman's Legs Hadn't Got in the Way?
This question is truly the nub of LBW. If the ball wasn't heading for the wicket, then it can't have hit the leg before the wicket. It wasn't going to hit the wicket at all. Thus a ball that was going to the left or right of the wicket is not out, as is one that hit the batsman in what are, in polite cricketing circles, known as the batsman's goolies, because the ball would have gone over the wicket.
Incidentally, if the ball actually did hit the wicket after the pads (provided it dislodged a bail), then not out LBW. Not that this matters in any real terms, since the batsman is out 'bowled'. Bowled always takes precedence over LBW. It follows from this that the 'before' in LBW means 'in front of' rather than 'and then'.
Question Three - Did the Ball Hit the Batsman's Legs on a Line between the Two Wickets?
One might think this to be a rather irrelevant question. Its purpose is the same as that of the LBW rule itself - to prevent negative play by the batsman. If he moves away from the wicket area, he isn't likely to be batting too defensively, and so is offered an incentive for positive play as it decreases his chance of dismissal.
This question cannot stand alone. Just moving one's legs does not, on its own, constitute positive play, so in the event of a 'no' answer to question three, the umpire must ask himself question four.
Question Four - Was the Batsman Attempting to Play a Stroke at the Ball when it Hit Him?
This question only needs to be asked if 'no' was the answer to question three. If the umpire thinks 'Yes, he was attempting a stroke', then not out. If he thinks 'No, he wasn't', then the umpire must carry on with his questions. Again, encouraging positive play is the intention.
Question Five - Did the Ball Pitch (bounce) outside the Line of Leg Stump?
Most of the LBW rule is to discourage negative play among batsmen. Question Five's purpose is to discourage it among bowlers. The wicket, not the legs, is the bowler's target, and is all he must aim for. So, if the answer is 'yes', then not out. If it is 'no', then one final question remains. (The leg stump is the one nearest to the batsman's legs (given that he stands sideways). It is sometimes referred to as the on stump, as the one furthest from the batsman's legs is called the off stump.)
Question Six - Did the Ball Hit the Bat, or Gloves Holding the Bat, before Hitting the Batsman's Pads?
The bat must be the first line of defence for the batsman. But it does not have to be his second. If the batsman has hit the ball, but it appears to be heading for the wicket, then he can kick it away if he wants, or even tap it away with his bat6. So a 'yes' answer here means not out, and a 'no' answer completes the list of questions. The umpire can raise his finger (the index finger), and give the batsman out.
A Recap
The batsman may be given out if the string of answers is:
Yes, yes, yes, no, no.
Or:
Yes, yes, no, no, no, no.
The potential for borderline decisions is great. The bowler could have been just outside his ground. The ball could have hit the batsman just outside the line of the two wickets, pitched just outside leg stump, or glanced the faintest edge of the bat on the way through to the pads. Questions two and four are subjective. They depend on what the umpire thinks, not what he knows (or even thinks he knows).
Hawkeye
Modern technology can now make umpires look stupid. Replays have always been able to show that some decisions were obviously wrong, but we can now know that more are wrong than ever before. Channel 4 took over cricket coverage in Britain in the mid-1990s and immediately introduced a number of innovations. The 'red area' can be imposed on a pitch to show precisely where the line between wickets is. A shot of the wicket can be imposed on the image of the batsman to show whereabouts on the wicket the ball was heading.