Samuel Lover, an Anglo- Irish novelist, songwriter and painter who died in 1868, said, “Circumstances are the rulers of the weak; they are but the instruments of the wise.”

That is so true. In today’s deal, a wise declarer can benefit from applying perhaps the only bridge “rule” that always works.

What is the rule, and why might South not capitalize on it? He is in four spades, and West leads a fourthhighest diamond seven. As a secondary issue, what were West’s more successful opening leads?

First, South sees five potential losers: two diamonds and three clubs. He has only eight winners: five spades and three hearts. So, he needs either one trick in each minor (West has the club ace) or two diamonds.

Many declarers, knowing that West would not be underleading (leading away from) the diamond ace against a suit contract, will immediately play dummy’s jack. Here, though, after East takes the trick with his ace, he can return any card but a club to defeat the contract.

Assuming West’s lead is fourth-highest, the Rule of Eleven must work. Yes, it is much more commonly used in no-trump contracts, but it applies in suits as well. Seven from 11 is four. Since South can see three diamonds higher than the seven (dummy’s king-jack and his nine), he knows East has only one diamond higher than the seven, which must be the ace. So declarer should play dummy’s three at trick one. Then he can get two diamond tricks to make his contract.

At double dummy, West had only two losing opening leads: his low diamonds.