Leads when the opening bid was passed out by Matthias Huberschwiller

A: 2♣ - Your partner must have some values, but didn't bid because he was quite long in Diamonds. South also must have a pretty strong hand.

If you underlead the Spade King, you might fall into declarer's tenace. You need to make a passive lead and lead a small Club, which is a lot less risky.

Your result so far:

A: J♠ - Here it's quite the opposite. If one of your opponents has values, it should be North, since South showed a weak hand.

If they have Spade honors, they have good odds of being in dummy's hand. You need to try and set up your own tricks before they set up theirs.

Your result so far:

A: 3♠ - Even though almost all the points from your opponents will be in the South hand, you still need to lead your long suit, since it's where you have the best odds of setting up tricks.

Of course you could give a trick to declarer by leading them, but that risk is not so bad compared to the hope of making 2 or 3 long tricks there.

Your result so far:

A: J♠ - Against 1NT, you usually need to lead passively, since your side will be able to get back on lead several times. It's better not to give a trick away immediately.

North can have length in the minors, but not so many cards in the majors, so a Spade lead has a good shot at finding something in your partner's hand.

Your result so far:

A: 2♦ - Wow, what good news that they ended up in Spades. Had your partner doubled you would have passed it, converting the takeout to a penalty.

If you lead Spades, you might give a trick to the Queen for free. You need to try the most passive lead available and wait for your tricks to come, so leading unaccompanied Aces is out of question. That only leaves Diamonds.

Your result so far: