How many QPs for slam?

[Free]

Would have to analyze hand by hand, but your calculations seem right. Your rule obviously is at most as accurate as Lawrence's method. :)

[Cascade]

I think this is what you asked for.

 

I changed the orientation of the table - I hope that is not too confusing.

 

The distributions shown are precise 5431 means five spades four hearts three diamodns and one club etc.

 

Frequency 4333 4333:
       Low      9     10     11     12     13       Sum
 12      0      0      0      0      0      0         0
 13      8      3      2      0      0      0        13
 14     67     41      9      0      0      0       117
 15    108     90     19      2      0      0       219
 16     75    121     47      2      0      0       245
 17     24     71     72     10      3      0       180 2%
 18      4     28     56     23      2      0       113 2%
 19      1      4     18     31      4      0        58 7%
 20      0      0      4     17      4      0        25 16%
 21      0      0      2      3      9      1        15 67%
 22      0      0      0      3      7      1        11 73%
 23      0      0      0      0      2      1         3 100%
 24      0      0      0      0      0      1         1 100%
Sum     287    358    229     91     31      4      1000

Frequency 5332 3442:
       Low      9     10     11     12     13       Sum
 12      0      0      0      0      0      0         0
 13      7      6      0      0      0      0        13
 14     24     36     36      4      0      0       100
 15     43     87     82     26      0      0       238
 16     18     66    127     44      3      0       258 1%
 17      4     20     69     61     10      0       164 6%
 18      1      5     28     52     31      1       118 27%
 19      0      0     11     26     22      3        62 40%
 20      0      0      1     12     16      6        35 63%
 21      0      0      0      0      6      1         7 100%
 22      0      0      0      1      1      1         3 67%
 23      0      0      0      0      0      2         2 100%
 24      0      0      0      0      0      0         0
Sum      97    220    354    226     89     14      1000

Frequency 4432 4243:
       Low      9     10     11     12     13       Sum
 12      0      0      0      0      0      0         0
 13      5      4      1      0      0      0        10
 14     20     51     35      3      0      0       109
 15     27     84    112     14      0      0       237
 16      4     68    130     37      0      0       239
 17      3     20     78     74     13      0       188 7%
 18      0      2     31     46     18      0        97 19%
 19      0      0     11     20     30      4        65 52%
 20      0      0      1     13     25      2        41 65%
 21      0      0      0      1      5      4        10 90%
 22      0      0      0      1      2      1         4 75%
 23      0      0      0      0      0      0         0
 24      0      0      0      0      0      0         0
Sum      59    229    399    209     93     11      1000

Frequency 4531 4243:
       Low      9     10     11     12     13       Sum
 12      0      0      0      0      0      0         0
 13      2      6      2      1      0      0        11
 14     19     23     36     16      0      0        94
 15     16     46     99     81      8      0       250 3%
 16      1     33     86    106     26      0       252 10%
 17      0      4     42     75     42      3       166 27%
 18      0      3     15     41     45      2       106 44%
 19      0      0      1     12     42     11        66 80%
 20      0      0      2      3     25      8        38 87%
 21      0      0      0      0      6      6        12 100%
 22      0      0      0      0      1      3         4 100%
 23      0      0      0      0      0      1         1 100%
 24      0      0      0      0      0      0         0
Sum      38    115    283    335    195     34      1000

Frequency 4531 5143:
       Low      9     10     11     12     13       Sum
 12      0      0      0      0      0      0         0
 13      0      1      7      2      0      0        10
 14      2     10     33     45      9      0        99 9%
 15      1      9     56    124     47      2       239 21%
 16      0      4     27    102    114      6       253 47%
 17      0      0      5     59     98     11       173 63%
 18      0      0      1     21     75     17       114 81%
 19      0      0      1      6     34     15        56 88%
 20      0      0      0      0     14     21        35 100%
 21      0      0      0      0      3     11        14 100%
 22      0      0      0      0      0      7         7 100%
 23      0      0      0      0      0      0         0
 24      0      0      0      0      0      0         0
Sum       3     24    130    359    394     90      1000

Frequency 4540 5143:
       Low      9     10     11     12     13       Sum
 12      0      0      0      0      0      0         0
 13      0      1      1      0      1      0         3 33%
 14      0      3     14     27     35      8        87 49%
 15      0      4     23     81    126     34       268 60%
 16      0      1     12     71    136     60       280 70%
 17      0      0      6     29     79     57       171 80%
 18      0      0      0      6     44     42        92 93%
 19      0      0      0      1     11     41        53 98%
 20      0      0      0      1      6     24        31 97%
 21      0      0      0      0      2      9        11 100%
 22      0      0      0      0      0      2         2 100%
 23      0      0      0      0      1      0         1 100%
 24      0      0      0      0      0      1         1 100%
Sum       0      9     56    216    441    278      1000

[straube]

Thanks for running those hands. They seem to bear out that that SST rule is not useful.

 

I've come to doubt that tracking SSTs and not trump length is faulty because you need both trump and shortness to take extra tricks.

 

Say I have 6143 opposite 1534. I have here a SST of 2 but not even an 8-cd trump fit.

 

So if there's a rule of thumb after QPs have been found to help decide whether to dcb (go to the 5 level), it might look something like...

 

QPs + (value for shortness times value for extra trump length)= a certain threshold

[DinDIP]

SST could be helpful but you need to invert it. Simpler is to use something like this:

Investigate slam (i.e. move into DCB) if QP + shortness is >=21

 

For shortness count

if an 8-card fit: each void = 2 and each singleton = 1

if a 9-card fit: first void = 3, first singleton = 2, first doubleton = 1, second void = 2, second singleton = 1

if a 10+card fit: first and second void = 3, first and singleton = 2, first and second doubleton = 1

 

Note: shortages in both hands are counted but not when they are opposite one another (i.e. if you have a singleton opposite a doubleton and a 9+card fit you only count for the singleton).

 

Obviously this is only a guide: if you have an 8-card fit but a solid side suit then you should count void = 3 and singleton = 2. And if you have hands that fit well -- partner's singleton is opposite your three small -- then count more (3 in that case as you know the partnership has no wasted K or Q opposite partner's singleton).

 

Most importantly, this should only be used when you are starting to relay. With experience you'll find that rules/guides like this are of little (if any) value: I've been relaying for nearly 30 years -- on and off -- and never use this or any other guide. Instead, I just use a simple test:

 

If I locate partner's QP in the most favourable places is slam solid? If it is, can I find out that partner has that hand by the five level or, more accurately, can I stop at a safe level if partner doesn't have that hand?

 

This is where it gets a little tricky: if there is only one honour permutation that makes slam worth bidding, how likely is that permutation? That's difficult to judge -- it helps to look at the relative frequency of the different honour permutations when the hand opposite has 15/16+. (I.e. if partner has 6QP how often is that AA, KKK, AKQ, KKQQ, AQQQ and KQQQQ.) But that is onlya general guide: the exact frequencies are affected by the specific honours the relayer holds. In general, however, honour combinations with lots of one honour are less frequent than ones with some of all honours. So, if partner shows 9QP and slam is only good if he has three aces then be wary of DCBing unless it is clear that you can stop safely. (Note that in most DCB methods partner will bypass more steps with more honours so you need to be very wary if you're looking him to hold AAA rather than AKKQQ.)

 

Try this in practice: using the earlier example of 8 QPs and 3-4-4-2 opposite AQxxx x KQx AQJx. (Much better to have described the UNBAL hand but . . . ) Here Kxx Qxxx Axxx Kx is a great slam even with a wasted HQ so you should be thinking of investigating. But whenever partner has the HK you know slam is poor (at best a finesse and a 3-2 break, unless partner turns up with the SJ, when it's still at best a finesse). And it's also the case that partner is more likely to have the HK than the SK or CK. So, unless your methods allow you to distinguish between partner's different honour holdings in H then I'd be conservative and sign off in game. Which is exactly why this hand shouldn't have relayed when it discovered partner was BAL; rather, it should have shown its shape or, at least, its shortness and S length.

 

The best thing to do is practise a lot: you don't even need partner. Just get old hand records or bulletins from major tournaments and bid all the hands. (I try to bid at least 500 -- of all types, not just slam hands -- before playing in any serious tournament.)

 

David

[straube]

Thanks for a very useful post. Your rule of thumb seems right in that it accounts for both shortness and trump length. It also seems pretty easy to calculate at the table. Did you make this rule of yourself or did you find it somewhere? What do other folks think? Are the point awards about right? Seems about right to me.

[DinDIP]

Thanks for a very useful post. Your rule of thumb seems right in that it accounts for both shortness and trump length. It also seems pretty easy to calculate at the table. Did you make this rule of yourself or did you find it somewhere? What do other folks think? Are the point awards about right? Seems about right to me.

My once or twice a year partner or teammate (shevek) suggested many years ago, when others were learning our symmetric system, that the rule should be QP + shortages (in both hands, counting 3-2-1). I thought that was a bit much when we only had an eight-card fit so did a little bit of testing -- not much I hasten to add (because I don't use the guideline) -- and the results seemed to work.

 

But I can't emphasise strongly enough that more practice is the best recommendation.

 

David

[straube]

these are pulled from Cascade's simulations....

 

 

...............................fit...............shortness.............QPs.................slam success......qps under rule

4333 vs 4333............7...................none.................21...................63%..................21

4432 vs 4243............8...................db, db...............20...................65%..................21

4531 vs 4243............8...................sg, db...............19...................80%..................20

4531 vs 5143............9...................sg, sg...............17...................63%..................18

4540 vs 5143............9...................vd, sg...............16...................70%..................16

 

Your rule works pretty close. It seems like you need to give a bump for the 8 cd fit if there's a ruffing value. Notice that there's only 15% difference between hand sets 2 and 3. I imagine this is because only 1 ruff is usually to be had with an 8 cd fit.

 

I'm also a little surprised that 4333 vs 4333 yields a 63% chance of slam with only 21 QPs. Seems like most people's experience would suggest 22 are needed for balanced mirrored distribution.

[cherdanno]

I'll just mention that I've played a QP-based relay system for quite a while now and I really don't think of things in this way. My tendency is just to visualize possible hands for partner once the QP total is known and try to figure out what we can make opposite various holdings. It really depends a lot on the shapes and how the hands fit.

I still think this is only good advice in this thread. All of the other rules will make you a worse bridge player in the long run (compared to trying to visualize partner's hand in all such auctions).

 

So say partner has shown 8 QPs and 3-4-4-2 and I have AQxxx x KQx AQJx.  That's 19 if I did the math right.  Do I ask?  Still looking for rules of thumb here.

Well if you give partner perfectly fitting cards (♠K ♥A ♦A) then grand could be on a finesse. If you give him terribly misfitting cards (bad trumps, ♥KQ ♦A ♣K) then you could go down in 5, but opposite most badly fitting hands (♠K and heart wastage, or the previous hand with better trumps) small slam will be on a finesse. So it must be right to investigate slam.

 

However, you may also notice that it's better to be relayed than to relay when you are unbalanced. Also, the time to wonder whether you should investigate for slam is before you have told opponents his complete shape.

[straube]

The good advice I've received on this thread has always been accompanied by the admonition that visualization is the way to go. I've agreed, but I thought it might be useful to see if some guidelines could help.

 

We haven't discussed much such things as bad splits. That in combination with partner not having the right cards can also make the 5-level unsafe.

 

We also haven't talked about the probability of partner having the right cards based on his known shape. For instance, if partner has 3-4-4-2 and 8 QPs and I have AQxxx x KQx AQJx odds ought to favor partner having red honors over black honors. It's pretty important on this hand that partner have the SK.

 

So when I visualize, I have to factor in bad splits and the likelihood of partner having useful cards.

 

Visualization and experience are great, but I think doing simulations (like Cascade has done) is also useful. So is having a general idea of how many QPs on average are needed for various hand patterns.

 

My system does a pretty good job of having the balanced hand do the relaying and we all know that this is important. Even so, sometimes the unbalanced hand winds up captain and then getting a feel for whether the 5-level should be ventured is useful.

 

It's hard to determine whether to explore for slam until I know partner's exact shape. Obviously, distribution counts a lot toward deciding whether a slam can be made. My partner and I reverse relay when opener has a limited hand and sometimes we can end auctions early. I think more important is to organize our system so that the captain hand declares.

 

So yeah, I get it. I'm not going to get a rule of thumb that has much utility, but I think I've learned a bit by trying. Appreciate everyone's help.

[DinDIP]

The good advice I've received on this thread has always been accompanied by the admonition that visualization is the way to go.  I've agreed, but I thought it might be useful to see if some guidelines could help.

 

<snip>

 

So yeah, I get it.  I'm not going to get a rule of thumb that has much utility, but I think I've learned a bit by trying.  Appreciate everyone's help.

In my experience, it's hard to find rules that are useful, easy to use and sufficiently accurate. But the process of working out why they don't work is very valuable -- with the proviso that the process involves bidding lots of hands to work out why. (Simulations can help but are less valuable than bidding actual deals.) I found when I did this years ago -- trying to work out a better method of hand evaluation -- that I never did discover a new metric that met the necessary criteria (useful, easy to use and sufficiently accurate) but my hand evaluatiion skills improved significantly because of all the deals I examined, trying to ascertain why the new value did (or did not) work on a particular deal. So, keep on bidding those hands!

 

David