shyams, on 2015-September-01, 16:43, said:
Declaring 6NT: If spades split 4-1, odds of play change but I assume they are 3-2/2-3 (we're told both North and South got spade leads on the actual deal)
So, cash top three spades ending in dummy and lead the ♦7 from dummy.
(a) If East plays 2 or 3, we definitely duck knowing West is on lead.
(b) If East plays 8 or 9, we duck and hope for a 3-3 or an enforced overtake.
(c) If East plays J or Q, we win and play for split diamond honors -- i.e. finesse the ♦10.
If we succeed in ducking the first diamond trick to West, it should keep more squeeze plays options alive.
Declaring 7NT: I think we will be forced to take a double finesse in ♥. Even if the ♣ finesse succeeds, any successful squeeze positions in the red suits for the 13th trick look anti-percentage. So, it must be better to play for the ~25% chance in hearts first and then work out suitable squeeze positions in the minors.
I agree that one should take the double heart finesse in 7NT. If that holds, the minor suit squeeze on West has gone up quite a bit, although the club finesse is still a possibility. As the finesses are all against the same player, it will be a bit less than 12%, something like 1/2*11/23*10/22 I guess (10.9%). Add something for the QJ doubleton in diamonds. The squeeze plus the double heart finesse seems a better chance, as people say, but when West bares the queen of clubs you have to guess the ending. They will never allow the ten of diamonds to become a winner, so you cannot have both. I am still uncertain as to which is better (I would go for the double heart finesse then the squeeze as you do), and I have not tackled 6NT fully yet.
I prefer to give the lawmakers credit for stating things for a reason - barmar
Lambert asks "Spingold Final. Contract 6NT by South or 7NT by North on a spade lead?"
My guesses:
6N: Win ♠ cheaply. Lead ♦ to ♦T, unless West plays an honour. (If West plays an honour, then cross to ♥A and lead another ♦ towards ♦T). Win return and test ♦ If they are worth 3 tricks, then claim. Otherwise cash ♥K, ♠s ,♣A. If East has 4th ♦, then you have a show up squeeze. Otherwise finesse ♣J.
7N: Win ♠. Cash ♦KA. If ♦QJ drop then cash ♦T and ♥AK: If ♥QJ drop then claim otherwise cash ♠s. If East has the long ♦, you may have a show-up/double-squeeze otherwise finesse ♣.
If ♦QJ don't drop and you feel that East has sole control of ♦, then finesse ♣J and cash black winners hoping for a red suit-squeeze on East. But if you feel that West controls ♦, then finesse ♥ twice and ♣s once