MartenW

Over 1♠ an obvious double, I think 2♣ is really bad. However, if my hearts were xxx and my clubs AKQTx, I would bid 2♣.

Imps. [hv=pc=n&s=sa53hjdk87caqt832&n=skj72haqt93d9ck65&d=s&v=b&b=7&a=1c1d1hp2c2d2sp2np3cp]266|200|[/hv] 1♥ shows 4+♥ (I know, suboptimal), opps play WJO. Agree with the bidding so far? What should South bid now? Discuss the merits of both 3♦ and 3♠. How should North respond to both those bids? Currently the club slam is reasonable but not great, but how should the bidding go if some minor modification makes slam really good, e.g., North having ♠Q instead of ♥Q?

Very interesting topic. Since this post did not consider comparisons between all three available strategies (pass, invite, bash) I decided to calculate these strategies with the given data. Assumptions: The hand is as given and partner opens 1NT. Three situations are covered: matchpoints, IMPS nonvul and IMPS vul. In each situation 1/3 of the field passes, 1/3 of the fields invites with all 16-17 hands accepting and all 15 hands passing and 1/3 of the field bashes (bids 3NT). Results: All results are averages over all outcomes. Matchpoints: - Pass: 53.1% - Invite: 52.2% - Bash: 44.6% NV IMPS: - Pass: -0.51 - Invite: +0.23 - Bash: +0.28 VUL IMPS: - Pass: -1 - Invite: +0.39 - Bash: +0.61 These results seem to suggest that indeed passing or bashing seems to be a good strategy. Inviting seems to be never the best, however if you have to stick with one strategy for both MP and IMPS then inviting is best. I'm not sure how valuable this is, considering all play is double-dummy; but inviting is clearly worse off if the play is not double dummy, since defending becomes easier. However the possibility of finding a major suit fit when is not taken into account, which sometimes makes inviting more attractive. PS: NV IMPS the whole field actually loses -0.10 imp on average, this is because of the sublinear IMP curve, for example if you get +100 and two others -50, you get 3 imps while they both get -2, and imps are lost. I added +0.10 to these scores to make the average 0. Funny, I never realized that playing IMP pairs you lose imps on average.