Draw another arrow from your quiver

West leads the ♠2 against your 4♠ contract in this deal:

                ♠ A 10 4
                ♥ 10 8 5
                ♦ A 7 5
                ♣ A 8 7 6
♠ 8 7 6 2                     ♠ 6
♥ J 9 6                       ♥ Q 7 4 3 2
♦ Q 9                         ♦ K J 10 2
♣ K J 10 2                    ♣ Q 5 3
                ♠ K Q J 9 3
                ♥ A K
                ♦ 8 6 4 3
                ♣ 9 4

That's an awkward lead, isn't it? With a plain-suit lead, you could play the ♦A and another, win the return and lead a third round. If diamonds divide 3--3, your problems are over, and, if not, you can ruff your fourth diamond in dummy.

After the trump lead, you could still try and ruff the fourth diamond. You win the spade lead with the 9, and continue with ace and another diamond. West wins the ♦Q and plays a second round of trumps. When you concede another diamond, East can win with the jack, but has no spade to lead.

Does this line work? No. West can ruff East's good ♦J and play his last trump, leaving you with four losers.

Neither Plan A nor Plan B works. Is there a Plan C? Yes. Instead of trying to ruff the fourth round of diamonds in dummy, give up on that. Instead, you should ruff three of dummy's losers in your hand.

You first cash the ♥A K, then play to the ♣A and ruff dummy's remaining heart. Now you concede a club trick, win the spade return with the 10 on the table, and ruff a club. You cross to the ♦A and ruff dummy's fourth club in your hand with your last trump. You've taken five spades tricks, two hearts and two minor-suit aces. The ♠A is in dummy for your 10th trick.