Many people have trouble deciding when to raise after partner preempts. This hand is an example: at equal vulnerability, LHO passes, partner opens 3, and RHO overcalls 3. What now?
A K 9 K Q T 6 4 2 5 4 3 2
If partner is adhering to the «rule of two, three, and four«, his hand should be worth six tricks if clubs are trump, at most one if they are not. You should raise to 4 with one trick (to further the preempt) or with four (intending to make your bid.) You might raise to 5 with two tricks as a sacrifice (expecting the other side to make game) or with five. With three tricks, do not bid again — that is enough for your partner to make his 3 but not more, and might be enough to stop the opponents from making anything.
Is this hand worth three tricks, or four? You might conservatively count the AK as two and the KQ as one, and decide to pass; or you might decide that, since LHO is a passed hand, the A figures to be with RHO, meaning that your KQx is well placed and likely to be worth two tricks. Your extra clubs are nice, but aren’t going to take any extra tricks: with no shortness you won’t be ruffing any of partner’s losers.
Dealer North Both vul
At the table, my partner chose to call this a 4-trick hand, and with the A favorably placed, I made 4 for 130, exactly as predicted. Unluckily for me, our opponents guessed well to not bid again. At the other tables, N-S gave up huge penalties, going down after bidding on to 4M or 5. Had I been sitting North or South I don’t think I could have made myself sell out to 4 either.