Competition Problem 159b
South to make three no-trumps. West leads the ♥10.
Successful solvers: Ed Lawhon, Sebastian Nowacki, Zoran Sibinović, Rajeswar Tewari. Although this got fewer correct solvers than 159a (DR7), the reason for that is simply that not everybody stated the necessity to unblock the ♦Q in line B. I felt it was necessary to state that because if you donít, then I have to assume you didnít see the necessity.
North wins with the ♥J and leads a diamond.
A. If East plays low, South wins with the ♦Q and continues the suit, finessing the ♦10. East takes, perforce, with the ♦A and does best to lead a low club. South wins with the ♣Q and leads a spade, North playing high.
1. If East ducks, North cashes the ♦K and leads a club, South playing the ♣A and another club. If East cashes both clubs and the ♠A, the next spade to North squeezes West in the red suits; otherwise, as soon as North gets in with the ♠K a diamond exit throws West in for a heart lead into the ♥AQ.
2. If East wins the first spade and returns a high club, then Northís ♣87 become equals and declarer can set up a club for the eighth trick and simply lead towards the ♠10 for the ninth (several orders of play are available to achieve this result).
3. If East wins the first spade and returns a low club, South ducks, letting West win the trick. West does best to return a diamond but North wins and returns the suit to put West back in for a heart lead into Southís tenace, South having thrown a heart and a spade. South score the ♥Q and ♥A, North discarding the ♠2, and East is subjected to a criss-cross squeeze in the black suits.
B. If East rises with the ♦A, South must drop the ♦Q! Now whatever East leads declarer has several routes to success, some of which lead to the ending in A.3 without using Northís ♣87 as a threat.
Trap: If South fails to unblock diamonds in line B, East returns the suit, wins the first spade and returns a low club. West can be thrown in to lead a heart for declarerís eighth trick but Northís spade entry has to be used up to achieve that and so there is no endplay against East for the ninth.
See the solution to Competition Problem #4 for the recommended tabular format if you prefer not to write in English prose.
Hugh Darwen, 2018