Competition Problem 163a
West to lead and defeat South's contract of four hearts. Why is that lead needed?
Successful solvers: Nobody solved this to my satisfaction! That's because nobody covered declarer's best attempt described in the solution below, failing because South is squeezed on North's diamond winner and East then discards accordingly when West is thrown in to lead a club. However, I now think the problem is a bit too mean (and DR8 would be a bit vacuous), so I'm giving credit (i.e., 4 M.P.s) to those who found the need for continued spade attack, namely: Ed Lawhon, Steve McVea, Sebastian Nowacki, A.V. Ramana Rao, Zoran Sibinović, Rajeswar Tewari, Andries van der Vegt, Dick Yuen, Wim van der Zijden.
West must lead a low spade. Declarer does best to win with the ♠Q and lead the ♦K or ♦J. East wins and returns a low spade to the ♠A, West playing low. Declarer’s best try now is a heart to the ♥A followed by the ♥J, which West must cover. North wins with the ♥K and South comes back to hand on a third heart to run the ♦9, but East wins this and leads a third spade. North can ruff, cash the ♦J and throw West in on the last trump, but East discards from the suit South discarded on the ♦J and the defenders must come to a fourth trick in either clubs or spades. If South has discarded a spade, then West and East must both play a low club at trick eleven.
Suppose instead that the defence starts with three rounds of diamonds. Then on the third round South ruffs North’s winner! Declarer can now lead either a spade or the ♥J, in either case winning two spades and three hearts to give this position with South on lead:
North ruffs a spade and leads a heart, simultaneously squeezing East and throwing West in for a club lead, South discarding from the opposite suit to East.
If West leads the ♠K instead of a low one, the defence can follow the given line but then the third spade sets up a trick for South, who can discard a club loser on the good third diamond. If East leads a low diamond instead of the third spade, South ruffs it and reaches the above ending.
See the solution to Competition Problem #4 for the recommended tabular format if you prefer not to write in English prose.
Hugh Darwen, 2018