[Bbradley62]

http://tinyurl.com/2e3hsok

The 3NT bid is explained as 4-H; 4-5S; 10-15 HCP.

North made the call with a flat 8HCP, which seems perfectly reasonable. The explanation should match the action.

[barmar]

I'm surprised it bid 1♠ on the first round. I thought GIB bid up the line. Has that changed?

On the 2nd round, it probably didn't have a bid whose explanation matches this hand, but it was too good to pass. So whatever it bid, the explanation wouldn't match.

[Bbradley62]

I have three hands where GIB skipped his 4card D suit to bid his 4-card major after partner opened 1C, but they're all within the past week, so I conclude that he consistently bids that way but can't determine whether that used to be different.

I've previously gone around in circles about bids fitting descriptions, so I should probably just give up on that. 3♣ is explained as 17-20 total points, so 8HCP should be enough to bid 3NT (as actually happened) and 14HCP should be too strong to sign off in 3NT. Therefore, I was suggesting that the 3NT bid should be described as 8-13HCP rather than 10-15HCP.

[arigreen]

This problem is caused by GIB's confusion between HCP and Total points.

3C promises 17-20 total points, but to bid 3N GIB requires 25 combined HCP.

When partner promises 17 total points, GIB assumes it has at least 15 HCP. Thus, GIB reasons that it needs 10HCP to have enough to bid 3N.

In practice, when GIB simulates with this 8-count it finds 3N to be the highest scoring action, so it will bid 3N here most of the time.

It would probably be better if 3N in this auction showed something like 7-12 HCP, however it's not so easy to implement this. On this particular board, the meaning of 3N is not so important as long as partner always passes this bid.

[arigreen]

GIB will respond 1♦ to 1♣ with 4x5x, but will respond 1♠ with 4x4x.