The rule of 7

You are declarer in notrump, the opponents lead their long suit, and you have exactly one stopper in it, usually the ace. Count the cards in the suit in both hands, yours and dummy's together. Seven minus that total is the number of times to duck. Win the next round.

The ace can sit in either hand. Ax in dummy opposite xxx in your hand is still five cards, and you still duck twice. People who count only their own hand, or only the small cards, get a different number and hold up the wrong number of times. You also need a small card in the ace's hand for every duck, so Ax opposite xxx can hold up only once whatever the count says.

A hold-up does one thing. It runs the opening leader's partner out of the suit, so that if that defender later wins a trick there is no card left to lead back to the long hand. The leader's winners then sit there with no way in to cash them.

The rule is built on one assumption, that the opening leader started with five cards. Hold five between your hands and the defenders hold eight, so a five-card lead leaves three with the leader's partner. Duck twice and that defender has one card left, which goes on your ace at the third round. Hold six and the partner has two, so one duck is enough. Every row of the table works the same way. Seven minus your cards is the number of ducks that leaves the partner of a five-card leader with nothing when you win.

Five is a sensible guess. With eight cards out, a 5-3 split is the commonest before anything is known, about 47 percent of the time, and a player who leads a suit against notrump usually has length in it. The guess can be wrong in both directions, and the sections below show when the lead or the auction tells you so.

Count your tricks first. You have the ♠A, two hearts and three clubs on top, six in all. The diamonds give four more once the ♦A is gone, which makes ten, but you must lose the lead once to set them up. The danger is that the defenders take the ♦A and then enough spades to beat you.

Between your hand and dummy you hold five spades, so the rule of 7 says duck twice. Let East's queen win the first trick. East returns the ♠9, you play low again, and West wins with the 10 or the jack. West leads a third spade, East follows with the 8, and now you take the ace. East has no spades left.

Now knock out the ♦A. East wins it and has nothing in spades to lead back, and West's two remaining spades never score. You make ten tricks.

Take the ace at trick one and the hand falls apart. East wins the ♦A, returns a spade, and West runs four spade tricks. One diamond plus four spades is five tricks for the defense, and 3NT goes down one.

The rule is a starting count, and good players treat it that way. Larry Cohen, whose article on it is well known, says he never uses it, because the right number of hold-ups depends on the deal. Most of the time the rule and careful thought agree. These are the cases where they part company.

• The lead shows a 4-4 split. A fourth-best deuce means the leader has exactly four cards, so with five in your hands the suit is 4-4. Neither defender can be exhausted before the other, the defense can take at most three tricks in the suit, and holding up mostly gives a switch a chance.
• The auction shows a six-card suit. If East opened a weak two in the suit and West leads it, with five cards in your hands West has only two. One hold-up runs West out of the suit, and that is enough when the trick you must lose can go to West.
• You have nine tricks without losing the lead. Take them. A hold-up that gives the defense time to find a switch can only cost.
• A switch is more dangerous than the suit led. If the defenders can win a cheap trick and shift to a suit where you have no stopper at all, the hold-up hands them the tempo. Count both threats before you duck.
• The missing honor is with the leader. When the trick you must lose can only go to the long-suit hand, holding up does not stop that defender cashing the suit, and you may need to look for a different line.
• You have two stoppers. The rule was built for a single stopper. Holding the ace and king, think about what a duck would achieve rather than counting to seven.

At matchpoints an extra hold-up can also be right when the contract is safe and you want to see how the suit splits before deciding whether to take a finesse for an overtrick.

The Bath coup is the hold-up with AJx when the king is led. Declarer plays low, and if West continues the suit, the jack scores. West has to switch or give you a trick. It is a hold-up for position rather than for communication, and the rule of 7 does not count it.

In a suit contract the same idea turns up less often, because trumps stop the long suit running. It is still right sometimes to duck the opponents' suit once, leaving the defender who wins your finesse with no way to reach partner. The rule of 7 is a notrump rule, and most teachers present it only there. Holding up an ace in notrump is also one of the plainest safety plays, since it costs nothing in most layouts.

The defenders have their own counting rule. Third hand reads a fourth-best lead with the rule of 11, which often shows how many cards above the one led declarer holds. Their remedy against a hold-up is an entry to the long hand, and that is why a long-suit opening lead against notrump appeals most when the leader also holds an outside ace or king.

• Counting one hand. The rule uses the cards in both of declarer's hands. Axx opposite xx is five, not three.
• Holding up with two stoppers by reflex. The rule assumes a single stopper. Holding the ace and king, ask what you are trying to achieve before ducking.
• Ducking when the wrong defender has the entry. If the long-suit hand holds the card you must knock out, the hold-up does not cut the defenders' communication.
• Forgetting the switch. Each round you duck is a trick the defense can use to look at dummy and lead something worse.
• Applying it to a suit contract. In a trump contract the opponents' long suit is usually stopped by ruffing, and the count tells you little.