Posted 2021-October-03, 05:16
Interesting. My reasoning was as follows:
The hand is very marginal, we probably won't miss a game by passing. Partner will take action on 'any' hand that will make game good, so we're protected. Conversely, if the opponents have a game I probably don't want to sacrifice and don't want to tell them the layout of the board, so passing can actually gain a lot on defence.
Now let's check the vulnerability. Oops, nobody vulnerable, the most aggressive vulnerability for partscore bidding. How will I effectively compete the partscore? Easy, I have spades. If the bidding peters out on the 2-level I just bid 2♠ and we're all good. No good reason to open then1, and pass it is.
If we have hearts instead of spades the exact same applies, but competing the partscore becomes a lot more difficult if they bid to 2♠. So I'd open to protect myself from the 6 IMP loss with a double partscore swing, risking all the other factors mentioned above (and two more not mentioned: firstly partner may well push to a sharp, failing, game and secondly I play 2NT as a catchall invitiational or mild GF raise, so we might land in 3♥-1 when the field gets to play in 2♥= if opps have the minor suits but not enough values to compete further).
I agree with the ZAR evaluation that the hand is probably stronger with spades instead of hearts, but I don't think that is the decisive argument for bidding/passing here.
1Note that passing might miss a profitable sacrifice over their 4♥, for example, if partner has the perfect hand. But it's a game of percentages, and I can live with the odds on offer here.
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IMO: a poor hand -- not really "rule of 20" -- but 5 ♠ are a valuable asset -- so still well worth opening unless it would flout your partnership agreements.