This deal from Round 16 is a potentially tough play problem for NS should they reach 4.
Suppose South is declarer and West leads the 2?
Having won perforce in dummy it looks natural to cross to hand with the K and play a spade to the king. When that holds declarer must come to hand with a diamond, ruff a club, repeat that process and then play a spade. If West overtakes East’s queen, cashes the J and exits with a club declarer ruffs but can then play a diamond securing the last two tricks with dummy’s A and a diamond.
You can change the order of play, leaving the trump suit till last, but with the A onside you should be able to negotiate your way out of the maze to get home.
Across the four events 49 pairs reached 4, 31 recording 10 tricks.