Dealer North. Both Vul

                             ♠        K 8 4

                             ♥        9 7 4 2

                             ♦        J 10 8 2

                             ♣       J 9

          ♠        Q 7 3 2                           ♠        J 10 6 5

          ♥        10 8 5                            ♥        Q 6

          ♦        A Q 4 3                            ♦        K 7

          ♣       Q 4                               ♣       10 8 7 6 2

                             ♠        A 9

                             ♥        A K J 3

                             ♦        9 6 5

                             ♣       A K 5 3

The lead of a trump puts pay to being able to ruff two clubs in the dummy, and also ruffing two clubs in the dummy runs the gauntlet that you might get overuffed so where are the extra tricks coming from? 

Initially you have 2 trumps but after the lead the trump tally goes to 3 (free finesse of your Jack at trick 1), 2 Spades, and 2 clubs. Totalling 7 winners. If trumps break 3-2 then you can ruff one Spade in hand and 1 Club in dummy. So where must the 10^th tricks come from?

It has to come from the most important aspect of card play and that is setting up a second suit. Here the suit to establish must be Diamonds. Therefore after winning the first trick draw trumps in three rounds and immediately set about the Diamonds playing the 9 to fish out one of their high honours. When you regain the lead again persevere with Diamonds and eventually your 13^th Diamond will be established for your 10^th trick.

You made 3 trumps.  2 Spades, 2 Clubs, 1 Spade ruffed, 1 Club ruffed and 1 established Diamond.

You can also watch the following movie to see how the hand pans out. To view this programme you will need  to download htttp://www.haroldschogger.com/bridgevu.setup