Responding 1 diamond to 1 club

I played the following hand against the robots in a Robot duplicate recently:

My result after the robot wrapped up all 13 tricks was a modest 69%.  Had the robot been sufficiently thoughtful to convert to 6NT, given his double stopper in the suit that I was missing, we would have achieved an 89% board.  Admittedly, my sequence suggested perhaps a 0454 hand – if we had been playing XYZ, this would have been a simple case of rebidding 2♦ as a game-forcing checkback.  But I wasn't sure what the robot played in this situation so I decided not to risk being passed out in a part-score (yes, there were two part-scores among the 32 tables).

But that's not the point of today's blog.  When I looked back at the results, I was surprised (shocked, even) by the majority of human Souths whose first bid was 1♥, thus bypassing a perfectly good suit.  Of 32 players faced with this situation, 20 chose 1♥, one chose 2♣ (forcing, denying a four-card major), another went straight to 6♣, and 10, including myself, chose 1♦.  It didn't seem to matter much to the final contract which of the initial bids was chosen.

This is not a Walsh issue, in my opinion.  Walsh basically says that with a weak (non-invitational) hand that is worth only one bid, you will simply show your major if you have one over partner's opening 1♣.  Otherwise, with game aspirations, you start with a decent diamond suit and then use some form of check-back to uncover if your side has bypassed a four-card major fit and/or has the strength for game.

But here, you aren't looking for the best game, you're envisaging a slam right from the beginning.  What is that slam to be in?  Clubs, most probably, or hearts or no-trump.  Yet, there is still a possibility that 6♦ (or even 7♦) might be the top spot.

Apart from that, bidding diamonds first should have made it clear to my robot that 6NT would likely play as well as 6♣ and I would expect him to convert.

While I'm on the subject of this particular Robot Duplicate, the gift basket was definitely open and one board yielded a clear top which helped me get third place with 63%.  This deal illustrates the dangers of balancing when vulnerable after the opponents have found a fit, especially when you balance with the wrong action.  Had the East robot bid 2NT as a balancing call, his side would have found their (making) diamond fit and we would have been compelled to bid on to our (making) 3♠ contract for the par result.  And there would have been no story.

But, as you see, the robot chose to double despite holding only three hearts.  Had his unlucky partner kept his head (or his CPU, I suppose), they could have escaped for only 800 and an 11% board.  But somewhere (trick 4 to be precise) he lost his way and ended up going for 1100.  Surprisingly, every robot, when faced with the same auction to 2♠, doubled.  I guess this is a flaw in the GIB programming.  Incidentally, I was the only human to redouble.  Doesn't that seem like an obvious call with my chunky 14-count?