[tmj_]

I just played a hand in the day-long free game. I held ♠ AQT9xx ♥ -- ♦ J ♣ AKQJxx and the bidding went: 2C (by me) -- 2H (positive), 2S -- 4N (RKC for spades), 5S -- 5N (description says it promises all the key cards), so I just jump to 7♠. But then I see dummy: ♠ Jxx, ♥ KQxxx, ♦ Qxxx, ♣ x

What happened?!

[nullve]

What happened is that 5♠ promised 2 or 5 key-cards (as well as the trump Q) and the robot understandably thought you had 5. You see, the problem with opening 2♣ just because you have 10 or more tricks in own hand is that partner may never be able to figure out how little his hand is actually contributing. For that reason I like to play that the 2♣ opening must satisfy the rule of 31, corresponding e.g. to 22 hcp in a 5134 hand and to 19 hcp in a 6016 hand. Then I would have had to open 1♠ on your hand, and the auction might have gone

1♠-2♠
5♥-5♠ (Exclusion RKCB; 0 KC outside H)
P.

[barmar]

nullve, on 2017-March-12, 18:33, said:

What happened is that 5♠ promised 2 or 5 key-cards (as well as the trump Q) and the robot understandably thought you had 5. You see, the problem with opening 2♣ just because you have 10 or more tricks in own hand is that partner may never be able to figure out how little his hand is actually contributing. For that reason I like to play that the 2♣ opening must satisfy the rule of 31, corresponding e.g. to 22 hcp in a 5134 hand and to 19 hcp in a 6016 hand. Then I would have had to open 1♠ on your hand, and the auction might have gone

1♠-2♠
5♥-5♠ (Exclusion RKCB; 0 KC outside H)
P.

Note that the robots don't play Exclusion RKCB.