Percentages...

[Hanoi5]

So you reach a game which makes 98% percent of the time with the hand partner's bid. 27% of the time you'd make 6, but if you RKCB you'll wager getting just to 5 which is just 78% makable. Would you use 4NT and risk losing that 20% or do you calmly pass and miss a slam which could be on in 27% of the cases partner has bid what he had?

 

On the other hand, let's say those numbers were 90% (for making 4), 66% (for making 5) and 26% (for making 6). Do you take the same decision? Which one? Why? Why not?

 

If you haven't understood my question yet, this is what happened:

 

With hand A & B we got to 5 en route to 6 and went down 1. With hand B partner had stretched his values so he claimed I had stretched mine, so I ran 2 simulations:

 

If holding hand A and partner has what he showed, out of 100 hands game is made in 98% of the cases, 5 in 78% and 6 in 27.

 

If holding hand B and partner has what he showed, out of 100 hands game is made in 90% of the cases, 5 in 66% and 6 in 26%.

 

So, who made the worst mistake?

[kenrexford]

These percentages are too tight to believe, first of all, but also too tight to possibly care.

 

Partner got aggressive. You got aggressive. Both were plausibly reasonable, but the two waves added up to a Binsky.

[Hanoi5]

Yeah, well, it is the pecentage of the Deep Finesse analysis.

[hanp]

Are you saying that if partner gives shows the good number of aces then slam is 100%, and partner would show that number in all of your 27% of the hands?

 

From the data you gave it seems not possible to answer your question.

[Hanoi5]

From the data you gave it seems not possible to answer your question.

 

Are you saying that I have to go over every hand to check for what the answer to RKCB and then check whether the contract is makable?

 

The data is not that reliable, as I said I just simulated 200 hands, 100 per case, and then checked each against deep finesse which gave me the results I showed. I think those percentages are roughly correct. But since you're saying that, how should I tackle that problemin order to get the answer I want?

[Cascade]

After Blackwood you will sometimes bid a slam that fails.

 

Partner might have the key cards but some other feature is missing or a bad break.

 

So 27% slam makes but you might have bid it 35% (or whatever) based on the response you hear to Blackwood (or cue or whatever action you take).

[CSGibson]

If you just give the hands, this becomes much less convoluted, and you might actually get answers that can help you. Just sayin'

[Rossoneri]

Expectation of IMPs gained/lost? Would that help?

[Hanoi5]

I'll just give the hands:

 

[hv=w=sat8xxhkxdktxxcaj&e=s9xxhajtxxdxckqxx]266|100|[/hv]

 

I think we were not vulnerable. I believe forcing to game with east's hand (2♥ over 1♠) is a bit too much. I think there's no way of stopping west from asking 4NT after a 2/1.

 

I would also like to know how much can you wager by going to 5 trying to find 6. I have often gone down in 5, you see. Maybe I should stop using KC so much...

[cherdanno]

Your percentages are really meaningless for the decision. Say you know partner's hand exactly, you need two finesses to work, so slam will make 25% of the time; also let's say 5 will 99% of the time (because losing one of the finesses will set up enough tricks). There is still no point in trying for slam (even if you add some hands for partner where you only need one finesse).

[Stephen Tu]

If there is truly no alternative, and you either have to sign off in 4 or try KC, then to calculate it's a very simple (IMPs won when you make the slam * % of times you get there) - (IMPs lost from going down in 5 or 6 * % you overreach). If this is positive, then it's "worth it".

 

But I have a very hard time believing that there is no alternative. You ought to be able to structure the previous auction so there isn't a guessing game by the time you reach 4M.

 

I have often gone down in 5, you see. Maybe I should stop using KC so much...

 

Absolutely, going down in 5 often is a sign you have to improve your earlier auctions. You should not be stopping in 5 often, let alone going down in it often, after KC. 5 should only be going down opposite unlucky breaks, not routine 3-2 breaks. Like you are off 2 aces and the opps suit splits 6-1 and they get a ruff.

 

On the given hand I don't see at all why the west hand should feel forced to go to the 5 level opposite a 2/1. 15 pts semi-bal opposite a opening bid with a spade fit isn't enough to be in the slam zone when the hands don't fit that well, you should be able to diagnose this by the time East signs off in 4S.

 

going to 5 trying to find 6

You need a RKC change of attitude. You should be bidding RKC *intending to bid 6*, not *trying to find 6*, you are only stopping if you are off 2 keys, or a key + Q of trumps if only in 8 cd fit. RKC != slam try. RKC == slam avoidance.

[PrecisionL]

Yes, you need another approach to slam bidding. Very few slams should be bid with RKCB.

 

Cue bids are usually better and investigate below game.

 

Admittedly, that in SA or 2/1 15 hcp opposite 15 hcp are the tough hands to find slam.

[ArtK78]

Personally, I don't think that the West hand is so great that it will go past the 5 level opposite any 2/1 game forcing response.

 

But I will give you a problem that I had in the District 4 GNT this past weekend.

 

I held:

 

AKT9xx

AKQ

x

xxx

 

The bidding:

 

Pard - Me

 

1♣ - 1♠

2♣ - 2♦*

3♦ - 3♠

4♠ - ?

 

*2♦ was an artificial game force (Extended New Minor Forcing)

 

I decided that this hand was worth another call. I bid 5♥. Partner bid 5♠ and I passed. Partner held:

 

xx

xx

ATxx

AQJxx

 

Not the worst slam in the world (either a winning club finesse and only 1 trump loser or finding QJ of spades onside with a 3-2 break, and nothing bad happening (I don't think you can pick up QJxx of spades onside - you would have to shorten yourself twice and finesse the spades twice as well as wind up in dummy in the right end position - I don't believe that is possible if the ♣K is offside)).

 

In 5♠, one only goes down if QJxx of spades is offside and the club finesse fails. That is what happened. I was not the only one who got to 5♠ (there were 7 teams in the qualifying, so the event was played in a board-a-match movement, and each hand was played in 5 of the 6 matches), but our opponents stopped in 4♠ and won 12 IMPs.

 

So, the OP's original question could be asked about this hand - by going past 4♠ in search of slam I risked going down in 5♠, which is what happened, although the chances of going down in 5♠ were quite small, and the chances of making a slam opposite the right hand (replace one of partner's small spades with the ♠Q) were very real.

[cherdanno]

I wouldn't try for slam with your hand, and I don't think it's close at all. Even opposite fairly nice hands, 5♠ can be down often (partner can have a spade singleton, he can have ♣KQxxxx where two club losers are not so unlikely, etc.). On top of that, with a really nice hand like Qx x Axxx KQJxxx he could have cued 4♥.

 

Edit: I was talking about the 6313 hand in the last post, and what to do over 4♠. The earlier hand is obviously worth a slam try, but it is not worth forcing to the 5-level.

[rogerclee]

I think there's no way of stopping west from asking 4NT after a 2/1.

Not true.

[barryallen]

So you reach a game which makes 98% percent of the time with the hand partner's bid. 27% of the time you'd make 6, but if you RKCB you'll wager getting just to 5 which is just 78% makable. Would you use 4NT and risk losing that 20% or do you calmly pass and miss a slam which could be on in 27% of the cases partner has bid what he had?

Very tricky and something you will base heavily on your previous experience of bidding and making slams. You have to be reasonably sure when you get to slam that the odds are commensurate with the risks, something nigh on impossible a lot of the times. But to be able to stop in the 5 level with a 78% chance of making is very good IMO.

 

The scoring method is going to alter your percentages, but a 50% chance at a small slam can pay overall, but this has to factor in your chances of being able to stop successfully at the 5 level along the way. Normally your odds can be slightly higher because it does not take into account the oppositions lead or error. I often feel once you have made 2-3 "dubious" slams that the odds have to be stacking up against you and factor accordingly. Similar to rolling a single 7 at craps, compared to rolling three 7's in a row. A lot will be dictated by what you require to be successful from a set of boards and what level of success you already had.

 

I have never seen a thin bookie riding a bike and they make their living from percentages. But they know what their exact percentage is most of the time, we are rarely afforded that exact insight. A very easy guide for any partnership at any level is to review their success at slam bidding (non tactical bid slams) and adjust their valuation methods to give the best returns. If you are bidding and making 100% of your slams, you are normally leaving a lot behind on the table.

 

As George Bush previously stated, "in my experience, 99% of the time percentages are wrong".

[kenrexford]

I'll just give the hands:

 

Dealer: ????? Vul: ???? Scoring: Unknown

♠ AT8xx ♥ Kx ♦ KTxx ♣ AJ ♠ 9xx ♥ AJTxx ♦ x ♣ KQxx

So we now have both hands.

 

1♠-2♣

2♦-2♠

2NT(not two top trumps)-4♠(trumps will be a problem, and I'm not that good)

Pass

[bid_em_up]

I think we were not vulnerable. I believe forcing to game with east's hand (2♥ over 1♠) is a bit too much. I think there's no way of stopping west from asking 4NT after a 2/1.

1) I don't think East's hand qualifies for a 2/1 response either.

 

2) I dont think that West's hand should ever be bidding RKC after a 2/1 response.

 

3) If you are worrying about bidding 27% slams (and then, only when partner holds perfect cards), you need to rethink your approach.

 

jmoo.

[P_Marlowe]

I'll just give the hands:

 

Dealer: ????? Vul: ???? Scoring: Unknown

♠ AT8xx ♥ Kx ♦ KTxx ♣ AJ ♠ 9xx ♥ AJTxx ♦ x ♣ KQxx

 

I think we were not vulnerable. I believe forcing to game with east's hand (2♥ over 1♠) is a bit too much. I think there's no way of stopping west from asking 4NT after a 2/1.

 

I would also like to know how much can you wager by going to 5 trying to find 6. I have often gone down in 5, you see. Maybe I should stop using KC so much...

Hi,

 

2H is too much, unless you open rock solid, most would

open the west hand without the king of hearts, in which

case game is hopeless.

 

4NT opposite a min 2/1 is also fairly agressive, add the

Queen of spades to the East hand, and slam is stil hopeless.

 

West has a nice hand, but he should try to find out the honor

location of the East hand, and if East happens to be dead min.

or if he has something to spare.

 

A possible auction:

 

1S - 2H (1)

3D (2) - 4S (3)

Pass (4)

 

(1) The alternative is to sell the hand as limit raise in spades,

not my choice, but reasonable, or bid 2NT Jacoby, but some

require 4 card support for this bid :), so 2H it is.

(2) That is the tricky part, but if 3D promises add. values than

that solves the issue since West showes the strength of his hand

with 3D, because he is min for the call.

(3) min values, no slam interest

(4) see 2

 

With kind regards

Marlowe

[hanp]

Still agree with 2H and an experienced partnership should have no trouble stopping in 4S.