After declarer takes first 8 tricks and then leads k ♥ louie ruffing the k ♥ can exit with a club,( only two rounds of clubs played so far}. if south ruffs with the jack, louie will have three more trump tricks. if he doesn't ruff louie will have a club and two more spades by exiting with 10 of spades.End result louie beats the contract by one.