Posted 2015-March-17, 08:55
I agree with your initial pass over 2 ♥. You don't really know much about partner's hand. If partner has a very minimum opener, even 2 ♠ may be too high despite your distribution. If partner has more, partner may bid on thinking you have some points and again get too high. By passing, you allow yourself to potentially raise later in the auction and know partner will not expect much in your hand beyond the fit.
At your second chance to bid, the situation is entirely different. Partner has bid ♦ and RHO has bid 3 ♥. Several things follow from these actions. So it's never wrong to think through the implications of the auction so far -- both the things bid and not bid.
First of all, partner by bidding 3 ♦ has shown at least 4 ♦s and 5 ♠s. You have a double fit of at least 8 ♠s and 11 ♦s. If your side has at least 19 cards in two suits, it follows that your side can't have more than 7 cards in the other two suits. That leaves the opponents to have 19+ cards in those two suits. Even if those two suits break as evenly as possible, the opponents have to have at least a 10 card fit in one of them. It also tells you that the hand is likely very distributional. Distributional hands tend to have more total tricks in them than flat hands. Additionally, double fit hands also tend to take a lot of tricks.
Second, RHO has bid 3 all by himself/herself. That should indicate either a solid 6 card or very good 7 card or longer suit minimum probably with some extra feature that makes 3 ♥ close to making. RHO's partner hasn't raised and your hand hasn't bid. There's no sense of where all the values in the hand lie. So RHO has to be looking at something that assures that the bid isn't stepping into a pile of bad stuff, especially at IMPs.
Finally, if you apply the LOTT based on the above, it says that there are at least 21 total tricks in this hand. Even if it's off a trick or so, it still favors bidding 5 ♦.
I heartily agree with your rethink that 5 ♦ might have been a better bid at your second opportunity to speak. Part of good IMP play is to put the opponents to the test of whether to bid on or defend.
But with the actual auction, after partner doubles 4 ♥, you shouldn't sit for it.
Partner doesn't know much about your hand other than you have a ♦ fit and some values. OTOH, you know a lot about the hand that partner doesn't know. By having an 11 card fit, the opponents have at most 2 cards in the suit. They are at best 1-1 in ♦, so you have no more than 1 ♦ trick on defense. Likewise, in ♠s, the opponents have no more than 5 of them. Again, the best break that could be expected is 3-2, so the most tricks that you can get in ♠s are 2. That still requires an additional trick in ♣s or ♥s to beat the contract. But that's only with assuming the best possible breaks. If partner has extra cards in either suit or the opponent's cards don't break as well, 4 ♥ is likely to make even with a trick in one of their suits.
Here the ability to beat 4 ♥ is enough in doubt to follow the old IMP adage: "When in doubt, bid one more." So, bidding 5 ♦ is right, even if it doesn't work out.