Help
South plays 2♠.
I noticed some interesting double-dummy problems pertaining to this hand.
1. Make 2♠ on the lead of a diamond against any further defense.
2. Explain why the lead of the ♣9 defeats the contract but not the ♣J.
3. Explain why switching the ♠6 and the ♠7 lets the ♣J defeat the contract.
Bonus:
-Against 1♦, played by south, in addition to the 'obvious' lead of the AQ of hearts, tapping south, the only lead to set the contract is the ♣J, instead of the 9.
-Against 1♥ in the south, both club leads defeat it by one trick, in addition to the ♥A.
-The only way to defeat 1NT played by south is to squeeze declarer.
-The only way to defeat 1NT played by east is to squeeze declarer.