[AyunuS]

http://tinyurl.com/y7l3lbj5

Advanced robots, IMPs.

I'm shocked that rebidding 2♣ could be the best way to bid this hand. I'd think it would either be raised by partner with too few clubs, or seen as a psyche bid to the other team.

The fix: Well, honestly, it could've just opened 1NT. And if it deemed its hand too strong for that, it could've then rebid 2NT or 2♥ after my bid, but I think 1NT opening is the best here.

[steve2005]

1N is possible. But 2♥ rebid is so obvious.

[smerriman]

Ha. If you thought that was bad, basic GIB rebids 2♦ :/ I guess this is one of those edge cases when it thinks it's too weak to reverse (requires 18 total points) but doesn't take that into account when opening.

[AyunuS]

2♥ is actually not obvious to it since it plays a pretty strict 18+ points to do a reverse, and it only has 17. The problem is that if it doesn't open 1NT, almost everything either is 16 points or less, or 18 points or more, except 3♦, but that would also show 6♦, so it didn't like that either. This bid a like a hole in its system. It took it like 5 seconds to finally make this bid. If you're good at telling stuff based on time taken, it might be possible to tell when it makes this kind of 2♣ bid.

[steve2005]

AyunuS, on 2018-January-28, 01:11, said:

2♥ is actually not obvious to it since it plays a pretty strict 18+ points to do a reverse, and it only has 17. The problem is that if it doesn't open 1NT, almost everything either is 16 points or less, or 18 points or more, except 3♦, but that would also show 6♦, so it didn't like that either. This bid a like a hole in its system. It took it like 5 seconds to finally make this bid. If you're good at telling stuff based on time taken, it might be possible to tell when it makes this kind of 2♣ bid.

Gib counts points for shortness and it has two doubletons so should have enough for a reverse. Gib counts shortness even in spades the suit partner bid, now that is ridiculous.
Gib is regularly short a point or two in it's bidding, So 2♥ is way more obvious than 2♣.

[smerriman]

steve2005, on 2018-January-28, 10:45, said:

Gib counts points for shortness and it has two doubletons so should have enough for a reverse.

It deducts a point for an honor in a short suit, so the honor doubletons don't count for any shortness points.

AyunuS, on 2018-January-28, 01:11, said:

This bid a like a hole in its system. It took it like 5 seconds to finally make this bid. If you're good at telling stuff based on time taken, it might be possible to tell when it makes this kind of 2♣ bid.

As above the systemic bid is 2♦. The 5 seconds is GIB simulating a lot of hands, figuring out how the bidding would proceed for each potential choice, and deciding whether any bid results in a better outcome on average than a 2♦ bid.

It's not completely incomprehensible to see why the results of that simulation might cause it to prefer 2♣ over 2♦ (or 2♥) - a raise of 3♣ gets you to 3NT, so it's really just weak hands like 4324 which would turn out bad (but would that be worse than the result after a reverse)?

I'd rather GIB just opens 1NT if it doesn't want to reverse though.

[steve2005]

smerriman, on 2018-January-28, 16:51, said:

I'd rather GIB just opens 1NT if it doesn't want to reverse though.

Yes 1N makes a lot of sense. , Gib doesn't seem to consider it's rebids. So you sometime get silly hands with 6-5 where it later decides not to reverse and a 5-card suit never gets mentioned.

[virgosrock]

smerriman, on 2018-January-27, 17:48, said:

Ha. If you thought that was bad, basic GIB rebids 2♦ :/ I guess this is one of those edge cases when it thinks it's too weak to reverse (requires 18 total points) but doesn't take that into account when opening.

methinks GIBBO rarely reverses with such hands when it does not have a stiff.

vrock

[jdonn]

I have never seen GIB make a bid like this. I will have to take a look.