In the following problems, you have the opening lead in defense. The contract played is always a garde. Detail which can be important: you play in a friendly game, not a duplicata. You also use standard signalisation.
Declarer has fund in the dog:
17, K, 9-4, Q, 3
What is your opening lead before or in front of declarer? From the bottom?
Trumps being excluded, the suits should be considered one by one. Opening lead in is the classic one (long suit + some strength + short suit in the dog). The lead fall into the king of the dog, it's a lead which seeks fast overtrumping. But the weakness of the hand does not authorize to impose it as a good defensive hand. First, there is no guarantee to find the king singleton, then we condemn practically all spade honors if declarer ruffs. And if ever we obtain an overtrumping or an uppercut, we will probably weaken a stronger hand than ours. This lead would be excellent with a hand which can defend (6 or 7 trumps) but in this case, it's too aggressive for the partners.
As for the lead, it has the disadvantage to be a little bit passive. Moreover, with 2 hearts in the dog, the risk to fall in a long suit in declarer's hand is too high.
It remains the lead. Although this opening lead goes against the guiding principles of traditional opening leads, it's here the most dynamic opening lead, the only one which can leave a vague hope for the defense. Let us look at the most favorable scenario: if declarer ruffs the , the 15 and 14 of trump will be used effectively for uppercut in the third and fourth round of the suit. After striping our trumps fastly, we will be in good position to save the and/or the honors, because the taker will surely control one of these 2 suits (or even both). Moreover, if the are the weakness of the taker, we can hope for a partner with 6 or 7 trumps and 4-5 . He will undoubtedly appreciate the tempo gained by this lead.
Another advantage of this lead is to immediately clarify the situation of the queen seen in the dog. A defender with for example R-x-x-x-x in could hesitate to open the suit, fearing to set up declarer's queen.
It should be noted that this type of opening lead in a short suit must be done only with a weak hand and with a dog which encourage it. It should be avoided with, for example, Q-x-x in the dog.
Why the lead of the jack rather than the 7 ? If the taker has K-Q or if he ruffs, the jack will probably be lost, whether it is played the first or the second round. But if declarer holds Q-C and choose to insert an honor over the 7, we will lose the jack on the second round under the other honor. Moreover, since we would not lead the jack from J-x-x-x or even J-x-x, our partners will understand that we lead from a singleton jack or from J-x. This is a basic signal.
And from the bottom?
If the lead was attractive in front or before the taker, it is much less attractive from the bottom. As a general rule, it must be avoided to lead from the bottom in a suit when the queen of this suit has been seen in the dog. Imagine the smile of the taker holding Q-x-x-x-x and receiving a opening lead that set up his queen immediately. We will be satisfied here with a solid and respectful lead, in a word the ace of .
Declarer has found in the dog: 1, C-4, 10, 4-1
What is your opening lead, in any position?
Before thinking of our opening lead, it is appropriate to answer ourself some questions. First, which type of hand should have the taker? Answer: the presence of the 21 and the 20 in my hand and the Petit in the dog give the answer. Declarer has the excuse well supported and a solid hand in the suits, maybe 2 or 3 kings. What will be the long suit of the taker? Answer: the 2 spades in the dog and the singleton in my hand give a good indication. Do I have a strong hand of defense? Answer: I could be tempted to believe it but, if the long suit of the taker is , my trumps will disapear quickly. In fact, there is probably no strong hand in defense, since the defender with the spade holding (if ever there is one) will surely not hold more than 3 or 4 trumps. Why? Because declarer has bid with only one oudler (at best), he has long trumps for sure. My hand containing already 5 trumps, that won't leave a lot for the partners.
With these answers, we can adopt 2 lines of play. The first one is optimistic and consists to lead the long to bluff the taker by wishing that he will play the Petit quickly. This line of play implies that it is hoped that the taker does not have long and that its hand was of the type "one oudler, seven trumps and 2 kings". The second line is more realistic and consists to imagine the taker with a hand containing 9 or 10 trumps and long . With such a hand, the Petit of the taker will go to the end no matter what we do, it remains only to hope for a good spade holding in a partner's hand to save some points. We thus lead trump, which will also avoid us ruffing the declarer's losers with the 21 and the 20 (horror of the horror). And since we don't want to announce a hand of 7 or 8 trumps to the partners, we lead the 2 rather than the 3, with the idea to delay the cashing of the 20 and the 21 as much as possible, in order to obtain a discard from a partner who would have only 3 trumps for example.
Advantage to the trump lead thus, opening lead in hearts being also possible. But since ruffing declarer's losers with master trumps is seldom desirable, we will probably have to cash the 21-20 sooner or later. And we must admit that the lead from 5 blank cards is not a gift for the partners.