After the title screen, you can select the type of analysis you want SuitPlay to perform on the suit combination that you enter next. Standard analysis provides results similar to those found in the suit combinations section of The Official Encyclopedia of Bridge. Additional to the standard analysis you can select matchpoint analysis or imp analysis. More on these in section 5.
You may enter any suit combination with more than 4 and less than 13 cards in the combined North-South hands. For example:
North: AQT98 South: 5432
If the spot cards are not
significant, please use x's. SuitPlay replaces these x's with the lowest cards
available. In general SuitPlay runs faster and uses less memory if the cards in
a hand are sequential.
If you chose imp analysis
previously, SuitPlay will prompt you to specify the contract, (re)doubled,
vulnerability and tricks needed. For example, if you need 4 tricks from the
suit to make your vulnerable doubled 3NT contract, you would specify:
Contract: 3NT Doubled: Doubled Vulnerable: Yes Tricks needed: 4
SuitPlay calculates the optimal declarer play against optimal defence. The optimal line of play may depend on the goal you want to achieve:
- best line (highest probability) for a desired number of tricks; or
- line that yield (on average) the largest number of tricks; or
- best line of play at matchpoints or imps.
SuitPlay calculates these
simultaneously. SuitPlay assumes that there are as many entries as necessary to
either hand, and that the defence is optimal. The defenders know the location
of each card and they will falsecard if necessary.
Most suit combinations are
easy for SuitPlay to evaluate, and the results will appear quickly. However, SuitPlay
may require more than 5 minutes to evaluate certain combinations, and in some
rare cases the calculation will terminate for lack of memory before an answer
is obtained. This may be avoided by using sequential cards as much as possible.
The results of the analysis appear in a table, similar to Suit combination section of The Official Encyclopedia of Bridge:
Goal Succ Prob Tricks Line 5 26.5652% [A] 4 82.7826% [B] max 4.0313 [A]
If declarer needs 5 tricks
(Goal = 5) the probability of success is 26.5652% when using the optimal line
of play, denoted by the letter A. If declarer only needs 4 tricks the best line
is B, and the probability of success is 82.7826%. If the declarer wants to take
as many tricks as possible, he should use the line of play recommended for goal
"max". In this example he will score 4.0313 tricks on average when
following line A.
If you selected matchpoint analysis or imp analysis, an addition line appears:
mp-best [C]or
imp-best [C]These analyses are explained in the next section.
The matchpoint analysis and
imp analysis are special features, which you can select after the title screen.
These analyses have never been described previously in the bridge literature,
so they will be explained here.
The best matchpoint line
depends on what happens on other tables. SuitPlay assumes that your only concern
is to win over declarers at other tables that have the same problem as you
have. The line denoted with "max" is best for most suit combination
at matchpoints. However, there are exceptions. Try for instance AQT98 - 5432.
When comparing two lines of
play at matchpoints, it only matters how often one line wins over the other,
and how often it loses. It does not matter by how many tricks one line wins
over the other. One line is better than another line if it wins more often than
it loses. The "mp-best" line determined by SuitPlay wins more often
than it loses when it is compared with any other possible line of play for the
specified suit combination.
In rare cases there does not
exist a best matchpoint line. This is the case when every possible line of play
can be improved. The improved line can be improved again, and so on. Try for
instance AJ98 - K32. (In game theory, one would say, the optimal
strategy is not pure but mixed. The pay-off table can be written to file, see
section 7.)
Like matchpoint play, the
best line with imp scoring also depends on what happens on the other table.
Again, SuitPlay assumes that the declarer at the other table has to handle the
suit combination in the same situation as you have. Usually, it is best to take
a line of play that maximizes the chance for the number of tricks needed to
make the contract. However, sometime the next best line for that number of
tricks has a much better chance to get an overtrick or to limit the
undertricks. In the long run, such a line will be better. Try for instance 4
tricks from KQJ543 - 92 or 5 tricks from AKT98 - 2 at 3NT.
When comparing two lines of
play at imp scoring, SuitPlay computes the expected number imps per deals one
line wins over the other. One line of play is better than another when the
expected number of imps it wins is greater than the expected number of imps it
loses. The "imp-best" line of play determined by SuitPlay is better
than any other possible line of play for the specified suit combination.
An example is given in section 7.
After SuitPlay has presented
the results of the analysis, you may select a line of play [A, B, ...] to see
optimal declarer play. SuitPlay plays the North-South cards and you play the
defenders' cards. You may defend with any layout of defenders' cards in mind.
You play a card by typing the card symbol or "-" when that defender
is void. You may type 'x' for the lowest card available. Play continues until
one defender does not follow suit. Then SuitPlay indicates how many tricks
declarer wins. The play also stops at the beginning of a new trick when either
North-South or the defenders have no cards left.
During the play, you see the
following information around the table.
- cards in the current trick are highlighted;
- known cards remaining in hands are displayed;
- E & W cards of quitted tricks are displayed to the right and left of the diagram, respectively.
In the first menu you can
select "5. Save analysis option". Here you can enable write to file
and select which kind of information should be written. If you select "0.
[X] Enable write to file", SuitPlay will ask "Save analysis to
file" each time you quit the results of a suit combination. The
information will be written to the file SuitPlay.txt in the same directory as
SuitPlay.exe.
You can select which
information is written to file. Most options are clear, but the payoff table
may need further explanation. The payoff table can only be written for
matchpoint analysis or imp analysis. For each pair of lines of play, the table
shows how much better one line of play is compared to the other. A positive
number means that the row line wins over the column line. For matchpoint
analysis, the number is the expected percentage of deals the row line wins
minus the expected percentage of deals the column line wins. For imp analysis,
the number in the table is the expected number of imps per deal the row line
wins minus the expected number of imps per deal the column line wins.
An example may clarify:
North: Q543 South: AT2 Contract: 3NT Doubled: No Vulnerable: Yes Tricks needed: 2
The results give three lines of play. Let us compare line of play A with B. In the Tricks table one can see that A wins one overtrick imp in the following cases:
West - East prob. AB
xxx - KJx 7.1056% 32
Kxx - Jxx 10.6584% 32
KJx - xxx 7.1056% 32
--------
24.8696%
A loses one overtrick imp to B in the following case:
West - East prob. AB xxxx - KJ 1.6149% 23
And B makes 3NT (600 points) where A goes down (-100) in the following cases:
West - East prob. AB
Jxxx - Kx 6.4596% 12
Jxxxx - K 1.2112% 12
-------
7.6708%
The difference is worth 12 imps.
So line B expects to win
7.6708% * 12 imps + 1.6149% * 1 imp + 24.8696% * -1 imp = 0.6880
imps per deal over A.
Here is the complete payoff table:
A B C A 0.0000 -0.6880 -0.7041 B 0.6880 0.0000 -0.0161 C 0.7041 0.0161 0.0000
Jeroen Warmerdam
Papelaan 112
2252 EM Voorschoten
The Netherlands
email: info@suitplay.com
Internet: www.suitplay.com