Strategy Question

[awm]

Just curious about how people play the robot duplicates (not the speed events scored on total points). Do you mostly play normal bridge? Or try to do strange things to fool the robots?

[helene_t]

Mosly normal bridge except:

- Open 1NT whenever it wouldn't be completely absurd. GIB's passive lead style seems to make this profitable. I think.

- Take advantage of the knowledge that I have the strongest hand at the table. I might open a balanced 11 count in first seat and then I might pass partner's (forcing) response.

[gordontd]

Mosly normal bridge except:

- Open 1NT whenever it wouldn't be completely absurd.

A lot of people seem to do this, but it seems to me to just be a randomising strategy. Often you can get a good board from bidding your suits naturally, just because other have bid off-beat 1NTs. Or they miss 3NT by opening 1NT on an 18-count, or get too high by opening 2NT on an 18-count, or get too high by opening 1NT on a 13-count. I don't understand the rush to be declarer, since we get to play the hand even if we're dummy!

[gordontd]

- Take advantage of the knowledge that I have the strongest hand at the table. I might open a balanced 11 count in first seat and then I might pass partner's (forcing) response.

Yes, I think that's right.

 

The thing I notice that GIBs do is to over-bid a lot when they are passed hands. So it's unwise to raise a passed-hand GIB's response unless you have a bit extra.

[ArtK78]

Pass any invitational bid that GIB makes, unless you absolutely positively have a full maximum for your prior bidding. GiB makes very light invitations. On the other hand, GIB will accept your invitations on any pretext, so don't invite unless you have full values for your invitation.

 

Always assume that GIB is not underleading a king on defense. This is true 99% of the time.

 

Don't raise a possible 4 card suit on 3 card support unless you are willing to play in a 4-3 fit. GIB always assumes 4 card support for your raise.

 

And be VERY CAREFUL about jumping to game in a minor suit. GIB often takes jumps to 5 of a minor as showing 25 HCP or something silly like that, and it will bid one more.

 

And NEVER jump to slam. GIB will assume you have 33 HCP.

 

Before you make a jump bid in any auction which you have any doubt about, roll your cursor over the bid you are about to make to find out what GIB will think it shows. This may prevent a disaster.

 

GIB loves to lead from a short holding. This is even true against NT contracts (some might even say it is especially true against NT contracts). So, don't assume that GIB is leading from length.

[barmar]

I think there's been some improvements in GIB's raising slams to grand in recent GIB versions.

[helene_t]

Yes gib doesn't bid reckless grands anymore. It still bids reckless small slams though

[Bbradley62]

- Open 1NT whenever it wouldn't be completely absurd. GIB's passive lead style seems to make this profitable. I think.

I open 1N with lots of 14HCP hands (especially lacking a 4card major) that I wouldn't with a human partner, but not with 18HCP as Gordon points out is common.

 

Take advantage of the knowledge that I have the strongest hand at the table. I might open a balanced 11 count in first seat and then I might pass partner's (forcing) response.

I'll also raise partner's 1M opening directly to 4M with a minimum game-forcing raise rather than bid more gradually, knowing that it's unlikely we have slam and wanting to prevent opps from participating in the auction.

 

GIB loves to lead from a short holding. This is even true against NT contracts (some might even say it is especially true against NT contracts). So, don't assume that GIB is leading from length.

This statement surprised me, so I tried to verify it from my recent hands. I found it to be true in only 5 of the first 20 NT contracts I checked (GIB led his best suit the other 15 times), then I stopped looking. My strictly-from-memory impression is that GIB does lead a lot of doubletons against suit contracts.

[dicklont]

Mostly normal but splinters are useless.

The robot wil never act right on a splinter.

 

Does Lycier already know about this threat? :rolleyes:

[Phil]

Stretch your 1N openings to include awkward patterns with minor suit shortness. I've had mixed/negative results opening 1N too lightly. Never shade 2N unless there's a great trick source since GIB is aggressive in responding.

 

If you have an 11 point hand consider opening a four card major and passing 1N. I almost never pass a hand in best hand tourneys.

 

Don't feel like you need to make the book bid. For instance if I held kqxx xx xx AKJxx and partner opened 1h I wouldn't bother to show clubs since we are playing 3N, 4h or 4s here.

 

Otherwise, I try to use the tourneys to really practice getting inside the hand. If a good player is totally focused without distractions you should be able to average 65% and win maybe 1 in 3.

[mgoetze]

- Open 1NT whenever it wouldn't be completely absurd. GIB's passive lead style seems to make this profitable. I think.

GIB's being so horrible at bidding when you don't open 1NT makes this profitable. ;)

[helene_t]

GIB's being so horrible at bidding when you don't open 1NT makes this profitable. ;)

Yes, GIBs NT structure is fine while there are some holes in the constructive bidding after suit openings. The forcing 1nt response works fine but the 2/1 responses need more work. Also, the fact that opps play crapaletti makes it more attractive to open 1nt.

[diana_eva]

I used to open 1NT on anything. Then Clee pointed out it wasn't such a good idea. I haven't quite figure out why, but anyway I stopped opening 1NT on 4441 or hands with shortness. I haven't noticed any significant improvement. The logical conclusion was along the lines of "doesn't matter what you open if you can't make your contract" :P

 

On a more serious note, I came to think 1NT openers vs GIBs are over-rated. I still love to open 1NT on anything, but I'm not convinced it makes a big difference. Playing normal bridge is really OK as long as you're paying attention.

[1eyedjack]

Not a good idea to open 1NT with a singleton major. GIB will transfer into it on a 5 card suit headed by the 6 and leave you there. Opening with a singleton minor (in-range) seems to be less prone to issues.

 

Open 1NT with a 5 card major but then consider denying holding a 4 card major in response to Stayman. You may miss a 5-4 fit, but then there is a good chance that GIB will lead that suit and hand it back to you. If you succeed in getting to 3N having concealed a 5 card major, and have another weak suit outside, don't fear putting RHO on lead. He will lead your major expecting you to have at most 3 of them. Also consider denying a 4 card major when 4333 shape. But perhaps you think of that sometimes in human games anyway?

 

I see that quite a few players habitually open their shorter minor when a minor suit opening is indicated. This can work but I have a lot of bad experiences with my GIB partner raising the opened minor suit.

 

Consider opening a weak 2 with a full opener (but one which would reject a game try having opened 1). GIB partner's strength limit reduces the risk of this backfiring. But it does happen.

 

Generally speaking, if you can steer yourself into a reasonable playable spot and in the process conceal or lie about your shape, then in general you should expect that what you lose in fooling partner you will more than make up for by the opposing GIB placing blind faith in your honesty. Consider rebidding 1NT rather than 1S with a 4 card Spade suit. If you have a 4-4 Spade fit you may lose out. If you do not, the prospect of gaining through misdirection is rather higher than in a human game, which improves the reward to risk ratio.

[ArtK78]

One more thing.

 

When your partner GIB opens a weak 2 bid, raise to game on any excuse. I find that GIB often has surprisingly good hands for its weak 2 bids. It is amazing how often a reasonable hand opposite a GIB weak 2 bid will make game.

[diana_eva]

One more thing.

 

When your partner GIB opens a weak 2 bid, raise to game on any excuse. I find that GIB often has surprisingly good hands for its weak 2 bids. It is amazing how often a reasonable hand opposite a GIB weak 2 bid will make game.

 

I found that GIB often makes these weak-2 bids with no honors, and outside values (something like *any* 6-10 HCP with long suit, doesn't matter where those points are). You'd better have an honor in trumps if you're weak elsewhere :P

 

It used to be more conservative in the past, it had full openers for its preempts, but now it's friskier.

[Bbradley62]

I found that GIB often makes these weak-2 bids with no honors, and outside values (something like *any* 6-10 HCP with long suit, doesn't matter where those points are). You'd better have an honor in trumps if you're weak elsewhere :P

 

It used to be more conservative in the past, it had full openers for its preempts, but now it's friskier.

My experience is consistent with yours, but GIB seems to be unpredictable in this regard. Maybe it depends on vulnerability or seat? I would have expected it to open this North hand: [hv=nn=GIB%20N&n=SQ76532H8DA42CQ94&d=n&v=n&b=21&a=P1D(Minor%20suit%20opening%20--%203+%20%21D%3B%2011-21%20HCP%3B%2012-22%20total%20points)]300|200[/hv]

[mgoetze]

Some misc. notes:

 

- Be wary about opening unbalanced hands 2♣. GIB plays natural positive responses (ugh) and its bidding system over these is: opener gets one chance to try and make a descriptive bid, after that responder tries to guess which slam to bid with its second bid.

 

- If you use GIB's systematic superaccepts, you will be going against the field. The field always superaccepts with 3M. I've yet to see a case where the systematic superaccept led to GIB making a smarter decision, but I have seen it wrongside the contract!

 

- I tried opening my shorter minor for a while, to throw off GIB's defense. Unfortunately, this doesn't work so well because GIB N loves to pull 1NT to 2 of a minor. Also note that GIB's systematic opening with (34)33 shape is 1♣. If you open 1♦, it will simulate you to hold 4 of them.

[barmar]

- If you use GIB's systematic superaccepts, you will be going against the field. The field always superaccepts with 3M. I've yet to see a case where the systematic superaccept led to GIB making a smarter decision, but I have seen it wrongside the contract!

I agree that it doesn't take good advantage of knowing which doubleton opener holds. But I've never seen it wrong-side the contract, since it always just re-transfers.

[banrock]

Never ever ever try to bid game in minor suit. you can be showing GIB single suit with 10 pts & 6+ cards in suit in suit it will always and i mean always either take you out in NT, (often against opps suit bid with nothing but XX) with 'only' 3 card support, or put you in slam with 4 card support when it could have single raised you 2 rounds of bidding previously.

[mgoetze]

I agree that it doesn't take good advantage of knowing which doubleton opener holds. But I've never seen it wrong-side the contract, since it always just re-transfers.

Well there is usually one answer where no retransfer is available e.g. 2NT-3♦-4♦.

[Siegmund]

I approach the tournaments primarily as declarer play practice, with a tiny bit of hand evaluation on the side. As such I prefer it when normal people have normal auctions. When I open 1C and rebid 1NT on my bad 14 count, it annoys me to get random noise added by the people who deliberately lied to the robot. Annoys me in a way that people playing a different system wouldn't.

 

I do find I bid differently with my 11s and 12s when I know partner is weaker. But I have yet to see any systematic advantage for the people who open 1NT on everything under the sun. Eventually it causes them to miss their 26-point 3NTs and get to their 23-point 3NTs, and it's hard to turn a profit doing that.

 

There are plenty of interesting bidding decisions on the competitive hands or on the "is it worth a slam invite?" problems.

[barmar]

Well there is usually one answer where no retransfer is available e.g. 2NT-3♦-4♦.

Jumping in the suit that the transfer goes to shows a doubleton in the suit of the transfer. So to show a doubleton ♦, bid 4♥.

[Bbradley62]

GIB loves to lead from a short holding. This is even true against NT contracts (some might even say it is especially true against NT contracts). So, don't assume that GIB is leading from length.

This statement surprised me, so I tried to verify it from my recent hands. I found it to be true in only 5 of the first 20 NT contracts I checked (GIB led his best suit the other 15 times), then I stopped looking. My strictly-from-memory impression is that GIB does lead a lot of doubletons against suit contracts.

Then, today I got these two...

[hv=wn=GIB%20W&w=SAQ62HJ75DQ97CA86&d=s&v=n&b=15&a=1N(notrump%20opener.%20Could%20have%205M.%20--%202-5%20%21C)PPP&p=HJ]300|240[/hv]

[hv=wn=GIB%20W&w=SAJT95HK9875DT4C4&d=w&v=b&b=4&a=P3D(Preempt%20--%207+%20%21D%3B%2010-%20HCP%3B%20%21DQ%3B%206+%20total%20points)P3N(2-5%20%21C%3B%203-%20%21D%3B%202-5%20%21H%3B%202-5%20%21S%3B%2013+%20HCP%3B)PPP&p=DT]300|240[/hv]

[barmar]

GIB's opening leads are based almost entirely on simulations based on the auction. The only rules it uses are after it decides to lead from a particular holding, it uses a table of lead agreements to know which of equivalent cards to lead (e.g. A versus K from AKx).

 

As I've mentioned many times, if you want to understand this process, read the Bird and Anthias books on opening leads. Their analyses were also based on computer simulations. However, because GIB is under time constraints that B&A didn't have, it can't simulate thousands of hands like they did, it only does a few dozen, so it's more likely to make mistakes due to sampling error.