[1eyedjack]

MP robot tourney, best hand South, Traveller 6766-1373182681-61380096

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They say that if you psych and get a bad result then you only have yourself to blame. Not so sure here. The 3H was described as (among other things) 4+ Hearts. That was not the pysch of course (just a bad bid in my view).

I bid 4C in full knowledge that it was natural, intending to retreat to Diamonds and divert a Club lead (with a fair wind and an entry the Club loser might go on a Heart). I had not allowed for GIB passing 5C response to RCKB in Clubs.

A principle of Blackwood, of whatever variety, is that you only generally use it if you are committed to slam opposite fewer than 2 missing key cards. GIB took a pessimistic view, to say the least, in resolving the ambiguity of "0 or 3 key cards", in the context of my earlier 2C opener.

MP, robot tourney, best hand South, Traveller 6845-1373184121-61390490

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It is a principle of RKCB that if as responder to Blackwood you appreciate that you have a 10 card trump and that the Blackwood bidder is not already aware of that fact, when asked about the Queen trumps, the 10th card is sufficient for a positive response.
Incidentally, when I moused over 2N before bidding it the description was "no information available". I am pretty sure that GIB knows it as a Spade raise based on 4+ cards.

[AyunuS]

But your thinking that it wouldn't pass 5♣ idea doesn't work. Once it uses RKCB, the suit is locked in. You can't bid any other suit or it'll put it back on that suit again. Tbh bidding 4♣ is probably what went wrong with the first one.

[1eyedjack]

AyunuS, on 2013-July-07, 04:56, said:

But your thinking that it wouldn't pass 5♣ idea doesn't work. Once it uses RKCB, the suit is locked in. You can't bid any other suit or it'll put it back on that suit again. Tbh bidding 4♣ is probably what went wrong with the first one.

I see your point. You are are saying that if I pull 6C to 6D then GIB will not pass that. You may be right. A human would (/should). Perhaps the psych is then exposed and its purpose compromised.

But to concentrate on the demerits of the psych is to miss the point of my posting the hand. Had I really held Clubs, then North should assume that I hold 3 key cards, not zero, and if 3 is not enough for 6C then 4N was the wrong tool.