Is there still room in the World Championship events taking place in Philadelphia this October? As a moderate duplicate player, will I have more fun as a spectator, a player, or an online kibitzer?

—  Tiny Tim, Kansas City, Mo.

ANSWER: Yes, you can still sign up to play, and although preregistration is encouraged (see here), you can also simply turn up and play in what rates to be the tournament of a lifetime. In almost all other world championships, you would need to qualify through national trials or zonal events, so make the most of your chances here.

Dear Mr. Wolff:

A recent bidding problem featured this hand: ♠ J-9-3-2, ♥ A-K-Q-2, ♦ —, ♣ A-J-10-7-4. You opened one club and rebid one heart over your partner’s one-diamond response. Now your partner bid one no-trump. You passed, settling for what you thought to be a reasonable contract, without risking getting too high. I would have invited to game by bidding two no-trump. Any thoughts?

—  Risk-Taker, Muncie, Ind.

ANSWER: I was suggesting that I was about a spot-card short of an invitational bid. Even the club nine might have made me feel more optimistic about getting four or five club tricks facing a doubleton club.

Dear Mr. Wolff:

What are the rules when an opponent makes a call and his partner forgets to alert it on time? Does the next player (who passed before the alert) get to reconsider?

—  Mulligan, Lorain, Ohio

Dear Mr. Wolff:

Recently you ran a problem featuring this hand: ♠ K-10-9-2, ♥ Q-3-2, ♦ J-6-5, ♣ K-9-4. In the auction, this hand passed over RHO’s one club, heard one diamond on his left, and one no-trump from partner. You described this as strong, but how can this show 15 points if both opponents have bid and the featured hand has nine?

—  Doubting Thomas, Pleasanton, Calif.

ANSWER: I’m not sure if you are overly trusting of the opponents or cynical about your partner. In these sequences I always trust partner and mistrust the opponents; they frequently respond light when they don’t fit their partners’ one-club opening. If partner has what he says, one opponent is lying — I assume it’s LHO!

Dear Mr. Wolff:

With this hand, ♠ Q-4, ♥ A-Q-9-3-2, ♦ A-2, ♣ A-Q-7-4, you asked what you would rebid after you had opened one heart and heard a one-no-trump response. You suggested either a direct rebid of two no-trump, or two clubs (followed by a correction to two no-trump if partner took a preference to hearts). What are the pros and cons of the two actions?

—  Fielder’s Choice, Dallas, Texas

ANSWER: The advantage of bidding clubs, then no-trump, is to get to clubs when it plays better than no-trump, and keeping the auction low if necessary. The advantage of bidding no-trump directly is that facing, let’s say, a 3-2-4-4 eight-count, you might stop at the two-level and miss out on a makable no-trump game or even five clubs.