Computer says NO

[pilowsky]

I rely on the GIB double-dummy to tell me if a contract is makeable or not, and to find out where I mess up. Here is a hand that came up in an ACBL Daylong (ACBL MP 1 2020-02-11). Of course, I am posting it to show off. GIB assured me afterwards that it was 4♥-1, but at Trick 1 I was pretty sure there was a way to make. Here is the hand, and below, the link to the way I played it. Is there a crafty bridge term for the play, or was I just lucky? It seemed makeable to me.

The lead from West is ♦K - GIB always underleads. As you will see from the link, according to Double-dummy this means the contract should be 4♥-1.

[hv=pc=n&s=sk842hat42dq97caq&w=sj76hk8dak6c87654&n=saq5h9763d32ckjt3&e=st93hqj5djt854c92&d=e&v=e&b=6&a=p1np2c2hpp4hpp]399|300[/hv]

https://tinyurl.com/ub3lagj

Naturally, I played terribly in the rest of the tournament.

[gordontd]

Gib misdefended. You induced it to ruff with a natural trump trick, which you over-ruffed.

[pilowsky]

lol, so it did, thank you. Lucky for GIB robots don't abuse each other.

[Cyberyeti]

lol, so it did, thank you. Lucky for GIB robots don't abuse each other.

 

Yup, if GIB ruffs with the Q or J or discards you can't make it

[gordontd]

lol, so it did, thank you. Lucky for GIB robots don't abuse each other.

Don't forget to try this again - when you have inescapable trump losers, this is one way to avoid them. I think people are even more likely to get this defence wrong than robots.

[Cyberyeti]

Don't forget to try this again - when you have inescapable trump losers, this is one way to avoid them. I think people are even more likely to get this defence wrong than robots.

 

People with half a brain never get this wrong, they've seen AQ♣, Q♦, know you have K♠ so you don't have ♥AK therefore you can't make unless they ruff low.

 

To persuade them to ruff low, make them do this before they work this out, win the first club with the ace, overtake the Q and play the third club immediately

[pilowsky]

Thanks for that Maybe we should call it the "Dolphin" they can get by with half a brain.

[dsLawsd]

Nicely done. Never say never as software has limited imagination.

I call it an instantaneous inverse trump coup.

Declarer always has an advantage and we never give up.

 

Thanks for the fun!

[maartenxq]

Gib misdefended. You induced it to ruff with a natural trump trick, which you over-ruffed.

There is a simple rule of thumb for this: Never (almost) ruff with a natural trump trick, but rules of thumb or not for computers.

 

Maarten Baltussen

[gordontd]

There is a simple rule of thumb for this: Never (almost) ruff with a natural trump trick, but rules of thumb or not for computers.

A corollary of this is that it if you are going to ruff a trick where you know declarer can also ruff, it's often better to ruff low and get over-ruffed than to ruff high and give declarer a discard.

[3338231]

Your opening statement mentioned GIB double-dummy.

Of course, that can also be double dummy to the defense.

 

If opening leader plays KD, AD, KH, there is no way

for you to make 4H.

[msjennifer]

Excellent play to bluff the ROBOT. May work sometimes in real play too.

[AL78]

A corollary of this is that it if you are going to ruff a trick where you know declarer can also ruff, it's often better to ruff low and get over-ruffed than to ruff high and give declarer a discard.

 

Or ruff with a non-winning honor card which might promote a trump winner in partner's hand if declarer overruffs (e.g. if you hold Jx and partner holds Qx in trumps).