A 4-2 Minor Game

[Incomplete analysis]

The only game that makes is 5 ♣ by South.

In notrump, the defense leads a diamond, aiming to kill the North hand's entry before declarer has time to unblock the hearts.

Against spades, the defense gets three trumps and an eventual club or diamond.

Against hearts, East must lead the ♦ Q. (If West is on lead, a low diamond.) This is an attempt to kill the diamond entry to North before trumps are drawn. If North ducks the lead, East continues the ♦ 10. A heart is lead to South's queen, but then declarer has a problem drawing trumps.

Suppose declarer tries the spade ace and spade ruff and draw trumps. Now he can draw trump, but he is out of trump, and West has two spades and a good diamond.

Indeed, killing the diamond ace will hold declarer to 9 tricks.

Against diamonds, the defense leads a heart. It is very hard to manage 11 tricks for North/South here, and, in fact, according to my double-dummy solver, they can actually be held to nine tricks.

Against clubs declared by South, if West leads a diamond, North wins, takes three hearts, pitching a diamond and spade from South, then ruffs a diamond in hand. Then the spade ace, spade ruff, and another diamond, ruffed in hand, and finally a spade ruff by North, East forced to under-ruff, leading to this position:

When North leads a diamond off dummy, he scores the club queen, and loses the last two tricks.

The same position can be arrived at if West leads a spade or a heart.

So a club lead from West is the last option, and that obviously has its own problems.

If West leads a low club, declarer wins the ♣ J in North, crosses to the spade ace and a spade ruff, then the heart queen and three rounds of clubs, dropping West's king. Then the a diamond to the ace and three more hearts. The defense gets a diamond and club at the end.

If West leads the ♣ K, declarer wins the ace, wins the spade ace, ruffs a spade, crosses with a heart and takes the club queen. Then he crosses to dummy and plays four hearts, pitching a diamond and spades. Now a diamond ruff scores the ♣ 2.