Against your solid-looking slam, West starts with the ♠9. How can you make sure of 12 tricks?
After dummy took the opening lead, declarer paused to take stock and saw that he could count 11 tricks, which meant he would need to develop an extra trick in one of the red suits. At trick two, declarer cashed dummy’s second high spade and led a diamond to his queen and West’s king. West found the sensible exit of a spade, forcing declarer to do all of the hard work on his own.
The contract now depended on making four tricks in hearts and that suggested gathering as much distributional information as possible before touching hearts. After taking the ♠Q J, throwing diamonds from dummy, declarer cashed the ♦A. East showed out, revealing the 5-1 break. Declarer continued by cashing the three club winners.
When West discarded a diamond on the third club, he was marked with an original distribution of 4=2=5=2. This allowed declarer to be sure that East had a starting shape of 3=4=1=5. So, declarer cashed dummy’s ♥A and ♥Q, then led dummy’s ♥4. When East followed with the ♥9, declarer covered this with the 10. The ♥K was his 12th trick. The full deal: