[mgoetze]

This board just cost me 1st place in a robot duplicate.

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GIB West leads ♥2, what do you play from dummy?

[wank]

mgoetze, on 2011-July-09, 04:17, said:

This board just cost me 1st place in a robot duplicate.

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GIB West leads ♥2, what do you play from dummy?

2 options imo. the ace which shouldn't work against a real player but which i suspect would confuse gib enough for you to establish a spade trick.

or low which is the % play in the suit in isolation

[mgoetze]

wank, on 2011-July-09, 06:03, said:

2 options imo. the ace which shouldn't work against a real player but which i suspect would confuse gib enough for you to establish a spade trick.

or low which is the % play in the suit in isolation

So you think GIB won't lead from J10xx often enough for the 9 to be an option?

[semeai]

If we know West led from 4 cards and had to lead this suit, then low would be the percentage play as there are 9 Hxxx-Hx or xxxx-J10 distributions and only 6 J10xx-xx distributions. However, I'd hate to lose to xxx-J10x if GiB can lead low from 3 small. So, if the auction had been something like 1N-3N, I think I'd just stick in the 9.

But there's also the factor that it's our suit and GiB knows we're 4-3 in it. Given GiB's analysis is double-dummy, I suppose this would make J10xx a less likely lead, as GiB likely believes we'll pick up Jxxx or 10xxx in its hand anyways. I don't know how much GiB's leads are based on simulations vs heuristics, though. I think if GiB can't lead low from 3 small, I play low. If GiB can lead low from 3 small, I'm still worried enough about a passive lead from xxx-J10x that I stick in the 9.

[BunnyGo]

I've been recently noting that GIB frequently tries to lead its partner's suit. It even will lead dummy's suit in this attempt. I'd play small, expecting to try and pick up the heart suit. GIB will not usually lead its own 4 card suit when Dummy has advertised that suit as well, but will lead a doubleton or xxx when Dummy has that suit.

Just some ideas I've been playing with recently,

Ben

[Bbradley62]

I'd expect GIB would lead the deuce from any four-card holding (except for ones specified in standard leads of an honor, which doesn't apply here). So, West's chance of have both J and T are (3/5)(2/4)=30%, chance of having neither is (2/5)(1/4)=10% and chance of having exactly one of J/T is 60%. GIB's convention card says he leads high from 3 small, so I wouldn't include xxx-JTx in the calculation. I'd play low planning to cash KQ then lead back to dummy, to win 70% of the time.

PS: I "showed my work" because I disagreed with semeai's numbers.

[mgoetze]

On the actual board I played the 9, losing to xxxx-JT. The extra overtrick would have given me 75% rather than 25%. In retrospect, I guess low would have been better.

[ArtK78]

When I first read the OP, I thought it was a joke. I would play low from dummy without any thought. Perhaps I have been playing too many robot duplicates.

Not only is it unlikely that LHR (left hand robot) has led from JTxx, but, if it did, it may pitch one on the run of the clubs. In fact, I wouldn't be the least bit surprised if both robot opps pitched a heart on the run of the clubs.

So, in real life, low is the percentage play without getting involved in any complex analysis.

[semeai]

Bbradley62, on 2011-July-09, 12:06, said:

I'd expect GIB would lead the deuce from any four-card holding (except for ones specified in standard leads of an honor, which doesn't apply here). So, West's chance of have both J and T are (3/5)(2/4)=30%, chance of having neither is (2/5)(1/4)=10% and chance of having exactly one of J/T is 60%. GIB's convention card says he leads high from 3 small, so I wouldn't include xxx-JTx in the calculation. I'd play low planning to cash KQ then lead back to dummy, to win 70% of the time.

PS: I "showed my work" because I disagreed with semeai's numbers.

Thanks, you're right. I ignored the 2 spot, but of course one doesn't play a random spot when leading, but the 4th best, so this contains information.

In my way of putting things: there are 7 ways to have Hxx2-Hx or xxx2-J10 and 3 ways to have J10x2-xx.