Competition Problem 162a
South to make four spades against any defence.
Successful solvers: Ian Budden, Ed Lawhon, Sebastian Nowacki, Zoran Sibinović, Rajeswar Tewari, Andries van der Vegt, Dick Yuen, Wim van der Zijden. Four solvers suggested DR6; one went for DR5 and one for DR4. I've gone with the majority.
South’s spades are going to bring pressure to bear on East in three suits.
A. If West leads a diamond, North wins and has the option to cash the second top diamond before leading the ♠Q. The play is somewhat simpler if that option is not taken, in which case South runs the spades until this position is reached:
On the next spade West discards a club, North a low heart. A heart from East is immediately fatal, allowing South’s ♥J to be established with a trump entry, and a club discard is equally fatal—for example, North can use the two aces to provide entries to establish a club trick by ruffing. So East does best to discard a diamond. Now come the ♦A and another diamond to West, forcing East to discard the ♣5. Best defence now is a club to East followed by a low heart on which South and West must play low. North wins with the ♥A and South ruffs out the ♣A. At trick twelve West is put in on the ♥K to give a club to North.
B. If West (better) starts with a club, North covers and East wins. East does best to switch to the ♦7.
1. If West plays low, so does North! East can do no better than continue diamonds. South can now, for example, win five trump tricks, North discarding hearts, followed by the ♦A to squeeze East. After the ♥A North leads either a club, ruffed by South, or a heart to West’s ♥K, depending on East’s discard. In the former case West’s ♥K is the stepping-stone to North’s good club as in A; otherwise, South’s remaining trump is the entry to the established heart.
2. If West covers, North wins and leads the ♠Q, followed by another when this holds (best). Two more trumps leave the position below, with East still to discard and South about to play another spade, on which North will throw another heart.
East must clearly keep three hearts and at least two clubs, so is going to have to unguard diamonds—and now the ♦6 comes into the picture.
(a) If East discards a club and a diamond—say the ♦Q—the presence of South’s ♦6 forces West to allow the second round of diamonds to be ducked to East. North wins the heart return and squeezes East again with the ♦A as in A.
(b) If East discards two diamonds, West has perforce discarded another club. A heart to the ♥9 and ♥A is followed by the ♣Q, covered and ruffed. West, thrown in on the ♥K, can cash a club winner but South discards a heart and accepts a diamond lead into the split tenace.
See the solution to Competition Problem #4 for the recommended tabular format if you prefer not to write in English prose.
Hugh Darwen, 2018