Competition Problem 170a
In each layout West leads and East-West are to defeat South's contract of three no-trumps.
Successful solvers: Sebastian Nowacki, Zoran Sibinović, and Rajesar Tewari were the only solvers to spot declarer's good try in layout Bóthe attempted avoidance play in clubsóand the careful defence needed to deal with that.
In each layout declarer threatens either to set up Northís diamonds, losing three times to Eastís ♦A, ♦K, and ♦10. This will fail only if the defenders can set up two tricks in the black suits before Northís long diamonds score. But the declaring side also has some interesting intermediate cards in hearts and clubs that defenders need to guard against. A defence might also be needed against a possible endplay on East in diamonds.
A. West must lead a middle club, covered by the ♣10, ♣K, and ♣A. Declarerís best shot is to play on diamonds, continuing the suit when East wins the first and returns a spade or club. However, Eastís leads on winning the first two diamonds will be, in either order, a spade and the ♣7. West discards a heart on the second diamond and when South lets the ♣7 hold East switches to a spade.
B. The solution given for layout A. fails because declarer can duck the second round of clubs to West to avoid a spade lead through the ♠AJ. However, here the defence can prevail by attacking spades from the outset! If declarer now plays as in A., Eastís spades will be set up before North can enjoy any diamond tricks. Instead, declarer can try for an extra trick in hearts, where a tenace can be set up against Westís holding, or diamonds if East can be forced to lead the suit. So at trick two South leads the ♥8, covered by the ♥9 and ♥Q and pinning the ♥7. North now leads a club. If East plays low the contract can be made by finessing the ♣Q and playing the ♥A and ♥K to squeeze East. East does best to discard the ♦5 and a spade, but North can now lead a club for an avoidance play, losing either this trick or the next to Eastís ♣K. In either case South can cash the spade winners and play a diamond to the ♦J. To avoid this outcome East must play the ♣K on Northís lead at trick three.
1. If South ducks, East returns a spade. South can try cashing the heart and club winners but East can safely discard the ♦5 and ♦10, keeping the ♦AK and three spades.
2. If South wins, the squeeze and avoidance play on East are not now available but now declarer has a split tenace in clubs and threatens a throw-in on West after losing a diamond to East. If East returns a spade, South can cash the remaining spade winner and throw West in on the fourth round of hearts. And if East instead returns a club South can throw West in on the third round of that suit instead, North taking care to discard the ♣10 on the third spadeóbut not if West has also taken care to play the ♣9 and ♣8 on the first two rounds, allowing Eastís ♣5 to win the third!
This defence applies regardless of when the first diamond is lost, but declarerís best attempt is to lead a diamond at trick four and play low from North! East must overtake Westís ♦9 with the ♦10 and return the ♣2. South wins with the ♣Q and leads the ♥2 to the ♥10 and ♥K, on which East must discard the ♦5. Now the spade winners are cashed and this is the six-card ending with South leading the ♠A:
(a) If North discards a diamond, West wins the club exit and returns a low heart. Trap: If West cashes the remaining club, North discards the blocking ♥6.
(b) If North discards anything else, West ducks the club, letting the ♣10 win if North still holds it, otherwise Eastís ♣5.
If West leads a spade in layout A., the contract can be made. South wins and plays three rounds of hearts, ending in North. East does best to discard the ♦5 and a spade, but Northís ♠K provides the necessary entry for the two club leads from North that are needed to achieve the avoidance play, should East play low on the first round. When East plays the ♣K, it is allowed to hold and now Eastís clubs can be eliminated for the diamond throw-in described above.
See the solution to Competition Problem #4 for the recommended tabular format if you prefer not to write in English prose.
Hugh Darwen, 2019