Playing IMPs.
This is from a BBO Challenge match playing against 3 basic GIBs. You are declaring 4♥ against the lead of ♥3 and East will follow with the ♥2.
Plan the play.
Spoiler Preliminary
Spoiler
If you draw another round of trumps, you will know that West started with 3, East with 1
Spoiler Final
Spoiler
Are you really stumped, or just confirming you have the right line of play?
Spoiler
If trumps are 2-2, you can draw trump, lead a club to dummy. If West wins the ace, you have lots of winners. If East wins the ace, you can pitch a spade on a high club and ruff 2 diamonds in dummy. No problem, you can't go down.
If you draw a 2nd round of trump and East has 3 trumps, you can lead a club to dummy, but if East wins and plays back a trump, you can only ruff 1 diamond in dummy so you have to pitch the 4th diamond on a club winner, and lead twice in spades to your hand to set up a spade trick.
But if someone has a doubleton spade (except ♠AK) and the last trump (or if you play a club before drawing a 2nd trump and trumps were 2-2), the defenders can manage a spade ruff and you will be down 1.
What about drawing 3 rounds of trump if trump are 3-1? You can only ruff 1 diamond, and if the club ace is with East, you only get 1 pitch, or if West ducks the club, you lose no clubs, but still have a diamond and 3 possible spade losers. So you will have to lead up to your spade twice and hope one of the spade honors are onside.
A priori, that is a 75% chance that 1 or both spade honors will be onside. But, what was the opening lead? Hint, it wasn't ♠A or ♠K so the odds are highly remote that the spade holding you should be worried about exists.
So the winning line of play is to draw 3 rounds of trump if necessary and lead a spade to your hand. Next play a club to dummy, high diamond(s) and ruff a diamond, pitch a diamond on the club (and a spade if West hopped with the club ace), and lead another spade from dummy.
You are pretty close to 100% on this line of play assuming that even a GIB would normally lead a high spade honor on opening lead.
Note that you can go down after drawing 3 rounds of trump if you lead a club to dummy. If East wins, and plays back a diamond, you only have 1 entry to dummy by ruffing a diamond but you have to lead spades twice.
If trumps are 2-2, you can draw trump, lead a club to dummy. If West wins the ace, you have lots of winners. If East wins the ace, you can pitch a spade on a high club and ruff 2 diamonds in dummy. No problem, you can't go down.
If you draw a 2nd round of trump and East has 3 trumps, you can lead a club to dummy, but if East wins and plays back a trump, you can only ruff 1 diamond in dummy so you have to pitch the 4th diamond on a club winner, and lead twice in spades to your hand to set up a spade trick.
But if someone has a doubleton spade (except ♠AK) and the last trump (or if you play a club before drawing a 2nd trump and trumps were 2-2), the defenders can manage a spade ruff and you will be down 1.
What about drawing 3 rounds of trump if trump are 3-1? You can only ruff 1 diamond, and if the club ace is with East, you only get 1 pitch, or if West ducks the club, you lose no clubs, but still have a diamond and 3 possible spade losers. So you will have to lead up to your spade twice and hope one of the spade honors are onside.
A priori, that is a 75% chance that 1 or both spade honors will be onside. But, what was the opening lead? Hint, it wasn't ♠A or ♠K so the odds are highly remote that the spade holding you should be worried about exists.
So the winning line of play is to draw 3 rounds of trump if necessary and lead a spade to your hand. Next play a club to dummy, high diamond(s) and ruff a diamond, pitch a diamond on the club (and a spade if West hopped with the club ace), and lead another spade from dummy.
You are pretty close to 100% on this line of play assuming that even a GIB would normally lead a high spade honor on opening lead.
Note that you can go down after drawing 3 rounds of trump if you lead a club to dummy. If East wins, and plays back a diamond, you only have 1 entry to dummy by ruffing a diamond but you have to lead spades twice.