A deal from a recent Manchester league match.
Dealer S EW Vul.
After South's opening bid of one spade North bid a conventional Jacoby two notrump to show at least a sound raise to four spades. South bid four spades to show no interest. West lead the ten of diamonds. Despite North's fifteen high card points and five card support this contract is not cold. How do you play?
Two lines of play are reasonable. The first is to take the spade finesse, if that loses then either the club ace will need to be onside or you will have to guess correctly that West has the ace doubleton of clubs. The second line is to cash the spade ace and then eliminate the red suits and exit with a spade, hoping to endplay West to lead a club or give you a ruff and discard, or if East wins, again to play the clubs successfully. Comparing the two lines, the first gains when West started with Kxx of spades, the second gains when East has the king of spades singleton. This difference is around two percent in favour of playing a spade to the ace. Playing a spade to the ace also gains when East has a singleton king and has four or more clubs to the ace and would be able to give West a club ruff if you took the finesse, though it is likely that West would have lead a singleton club. Also the elimination line works when East has Kx of spades and QJ, Q10 or J10 doubleton of clubs as you can cover when he plays a club through.