The Worst Possible Leads
There are few absolutes in bridge, but there's a general rule about leading a suit headed by an unsupported ace against a suit contract. “Unsupported,” means a suit such as ♥ A543. You can take this one to the bank: DO NOT lead low from this holding against a suit contract. That's as bad an opening lead as you will find. If the king is on your right, you may well be giving the declarer a trick he could never get on his own. You might also find the declarer or dummy with a singleton king in the suit and end up taking no tricks at all.
Eliminate the worst possible leads from your bridge play and watch your scores improve. These are bad leads because they give something to the declarer unearned. Remember, your worst possible move is to underlead an ace against a suit contract. Next worse is leading the ace in a suit without the king.
Also bad is leading the ace from that same holding. Aces are meant to take kings. If you start with an unsupported ace in a side suit against a suit contract, you are likely to fetch a bunch of low cards. You weren't dealt that ace to take 2s and 3s. It was meant to capture honors. Your partner might have the king in the suit, but so what? All you are doing is helping the declarer set up his “slow” tricks in that suit.
There will be times when the lead of an unsupported ace is okay, such as when you have a lot of cards in that suit (for example, AJ108765), and reason to believe your partner is short. If you lead the ace and find your partner with a singleton, you can give her a ruff. That's not going to happen often, however, when you have only four or five in your suit.
Another dreadful opening is the lead of a singleton or doubleton without reason, especially a doubleton. You will find many bridge players automatically lead a singleton or the top card of a doubleton. There are times when this can be very productive, but in many cases, it is not a good thing. You are likely to be helping the declarer set up a long suit. You may be picking off an honor in your partner's hand. You will learn when a short suit lead can be good. In summary on this point, give careful thought to any lead from a singleton or doubleton. Consider every possible alternative to leading a short suit. This lead is often misused, but when it's right it works.
A singleton can be an attractive lead when you know you are going to get in with trumps and your partner has some reasonable shot at getting in to give you a ruff. In that case, you lead the singleton, win a trump trick, and return to your partner's hand in another suit so she can return the suit of your void.
It's a rare day when you can get a ruff with a singleton trump, but it does happen, particularly when your partner has bid your singleton. On that occasion she is more likely to have the ace, so she can give you a ruff right away. If she doesn't, the declarer will win and start playing trumps — there goes your ruffer!
When you find that your partner is consistently making leads that you know are counterproductive, you will have to be tactful. Suggest that one day you and partner will agree not to lead from a doubleton unless your side has bid it. Using this approach you will be able to gain your partner's confidence and establish rapport.
A dismal lead is a singleton in a suit that the opponents have bid unless you are totally confident that your partner has the ace. You are most certainly helping the declarer when you lead a singleton in a suit that has been bid by the opponents. Experienced declarers can spot these singleton leads right off the bat and play the hand as though they can see all the cards.
When a suit has been bid by dummy, avoid leading that suit unless you have a powerful holding. Stay away from any suit that has been bid twice by the dummy or declarer. This admonition is important because the dummy will often have a five-card suit, and you will be helping the declarer set up the suit.
Avoid leading a suit when you have the jack but no supporting cards (10 and 9, for example). It's an especially bad lead to start with the jack from a doubleton in a suit that your partner has not bid. The same can be said of leading the queen from a queen doubleton. These are destructive leads unless your partner has bid the suit. Remember, the lead of a jack is not an attack. Similarly, the lead of a queen should never be seen. If the jack or the queen is part of a three-card sequence, then there is hope.
Sometimes you will have to lead an ace because you have no other choice. If you're dealt all the aces, something's got to give. Better to lead one of them than to underlead one. Your partner will understand when the deal is over and you show him you had no choice.
With all the prohibitions in mind you may think that finding a good lead is next to impossible. Actually, with experience you will find yourself the envy of the table for finding the lead that sets the opponents.