Here is a hand from the semifinals that presented a challenge in both bidding and play. At the table I was watching, Michael Kamil held it. In third seat, he held::
Partner dealt and opened 1 Heart. He replied 1 Spade. Partner now jump shifted to 3 Diamonds. What do you bid? Kamil made the interesting bid of 5 Spades. This bid was likely never discussed, but a likely meaning is that he is asking partner to bid slam if he has a control in clubs, the unbid suit. Partner duly bid 6 Spades with:
This auction cried out for a club lead, which was duly made. Now, how should he play it?
There are three possible lines: (1) duck; (2) win the ace and play another club; (3) win the ace, ruff a red card and draw trumps, then knock out the king of clubs.
If you try line (3), you succeed whenever spades are 4-3. You can draw trump in 4 rounds, play a low club to knock out the king, and can ruff a red card and use the long clubs. You also succeed if RHO has the stiff king of clubs when spades are 5-2. However, if spades are 5-2 and the king of clubs doesn't fall, you cannot get back to your hand to use the clubs because you will have used all your trumps.
If you try line (1), you succeed whenever LHO has the king of clubs, whether spades are 4-3 or 5-2. You will also succeed when RHO has Kx or Kxx of clubs when spades are 5-2. This line loses when the opening lead is a singleton, as you will go down immediately with a ruff. If so, and trumps are 4-3, then line (3) would succeed while this line fails.
Line (2) is inferior to either of the other lines, since you will go down whenever either hand holds Kxx no matter how spades split.
It is hard in the heat of battle to calculate the odds here. Kamil actually chose (3), unwilling to go down right away, and went down when the full deal was:
♥ A Q 10 7 6 5
♦ A Q 10 9 8
♣ A 7
♠ 5 2
♥ 4 2
♦ K J 7 6 3 2
♣ 6 3 2
♠ 9 7 6 4 3
♥ K 9 8 3
♦ 5 4
♣ K 4
|♠ A K Q J 10 8|
♣ Q J 10 9 8 5
|1 ♥||Pass||1 ♠|
|Pass||3 ♦||Pass||5 ♠|
|6 ♠ by South|
If he had chosen either (1) or (2), he would have succeeded.
At the other table, Geoff Hampson reached 6 Spades on a different auction and got a heart lead. On this lead, the play was easy. He ducked the heart, losing to the king, and eventually was able to draw trumps and throw all his losing clubs on dummy's hearts and ace of diamonds.