Markup of ACBLmerge reporting features

ACBLmerge Report Features

The ACBLmerge program was inspired by the program Evan Bailey wrote to merge hand records with the results generated by ACBLscore, the DOS based program used by directors. His software is currently used at Adventures in Bridge. The new ACBLmerge program provides enhanced functionality. The numbered sections below refer to the sample output shown above.

To obtain the ACBLmerge software click here.

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1. Top Header

The top header contains several hyperlinks. The first takes you to this page. The second allows you to save all the boards in Portable Bridge Notation (PBN) format. Many programs can read PBN format, for example the free Bridgify double dummy solver. Having the boards in PBN format saves a lot of typing.

You may jump directly to any board via the in-page navigation links. After jumping directly to a board, you can copy the URL from the browser and include it in e-mail or any other document which understands hyperlinks. For example, the following URL, with the #board_results5 at the end will take you directly to board 5 of the April 6, 2009 Afternoon Charity Pairs Game.

2. The Board

The board shows the board number, the board hands, the dealer, and vulnerability just like a standard recap sheet. A dash indicates a void suit. ACBLmerge uses standard font characters for the suit symbols, so you can readily copy-and-paste a single hand. If you try to copy-and-paste the entire board, you may not get what you expect; this is described further in Section 8 below.

3. Results for each Pair

The raw score (e.g. 140), and the matchpoints (e.g. 16.00) are shown and sorted in descending number of matchpoints for N-S, an idea borrowed from Evan Bailey. This presentation makes it easier to see how often each result was achieved and where you stand on the board. N-S players want to be near the top and E-W players want to be near the bottom.

To find where you are on each board you may use the search functionality in your browser. Ctrl+F will bring up a search dialog in both Internet Explorer and Firefox. Just type your last name and press Enter. To move to the next board in IE press Enter again or the Next button to repeat the search. In Firefox press Ctrl+G to repeat the search or simply press the Highlight All button on the Find bar.

For those unfamiliar with matchpoint scoring, you receive one matchpoint for each pair you beat and half a matchpoint for each pair that you tie. For a board played N times, (N-1) is the best possible matchpoint score, a “top”. Unlike team play (IMPs), the relative difference in raw scores does not matter. Thus if 3NT and 4 not vulnerable both make 4, then the pairs with +430 beat the pairs with +420 to the same degree that a pair making slam beats a pair that fails in slam. Then again if 3NT makes 3 and 4 makes 4, the +400 loses to the +420.

If a board is played fewer times than other boards, for example, due to a slow table, ACBLscore will scale up the matchpoint values, leading to funny values which are not integers or half integers. Director rulings that award Ave+ (60%) and Ave- (40%) to the non-offending and offending sides respectively, can also lead to strange looking matchpoint scores.

4. HCP total for each hand

Shows the high card point (HCP) for each hand, based on the standard A=4, K=3, Q=2, J=1 point count system. No adjustments are made for length and/or shortness.

5. Double Dummy Makeable Contracts

Shows all contracts that can be made if all players knew all four hands and bid and played perfectly. Since real bridge players do not see all the hands and therefore must bid and play based on the ensemble of hands consistent with the bidding and play up to that point, double dummy results must be taken with a healthy dose of skepticism. The double dummy line of play may require dropping an offside singleton king, underleading an ace, eschewing a simple 50% finesse for a low probability squeeze requiring exactly the right lay of the cards, and other plays that work on the given board but would not be the percentage bid or play. Many new players look at the double dummy results and feel they have done something wrong if they do not match the computer generated result. This is a serious misconception. To some extent, double dummy results are shown because it is a well defined and solvable problem, requiring only a few seconds on average for each board running on a modest computer using efficiently written software. Determining what should happen on a board is much more complicated and even then would involve assumptions about bidding systems, aggressiveness, and so forth, which vary.

The ACBLmerge double dummy results are complete. Every denomination is tested from each seat. By contrast the Deep Finesse results shown on Dealmaster generated recap sheets are incomplete. In the default setting, Dealmaster only computes the double dummy results for “likely” contracts. Sometimes it misses a good, or even optimal, contract. Usually this happens when the trump fit is poor, e.g. a 4-3 or 5-1 fit with strong cards. Thus, a dash on a Dealmaster recap sheet does not always mean the contract fails.

On the ACBLmerge output, a result such as 4♠ means that the contract can be made regardless of direction. A result like 3/4 means North/East can make 3 and West/South can make 4. A dash, as in -/1 means only South/West can make anything in hearts. Smaller indications in light blue such ♠5, with the number after the denomination, show the number of tricks that can be taken. Thus, ♠5 means 2♠ would fail by three tricks. Sometimes one actually cares to know just how many tricks a low level contract can be set. For example suppose you are vulnerable against not and the auction proceeds 1♣ 1♠ to you. Holding ♠KJ83 AT5 KQ72 ♣J4, you debate passing and hoping that partner reopens with a double, but decide to bid 3N directly instead. After you collect +660, you begin to wonder if defending 1♠* would have been more profitable. ♠3 would tell you that +800 had been possible.

If after a bit of thought, you are not sure what lines of play the computer has run through to reach its double dummy conclusion, you can load the board into a double dummy analyzer which will allow you to see the double dummy result for any starting line of play. My favorite program for this in Windows is Bridgify. It is free, has a clean, simple, intuitive interface, analyzes hands quickly, and can load hands from a PBN file. Conveniently, it is a standalone executable and therefore does not need to be installed. If you copy the executable bridgify.exe and help file bridgify.html on to a USB memory stick you can take it with you and run it from any Windows computer. The free Bridge Captain Double Dummy Solver is another alternative for Windows. Its interface is not as clean but it has the ability to compute the par contract and show how many IMPs were won or lost on each hand relative to the par contract.

6. Law of Total Tricks Calculation

The so-called Law of Total Tricks (LoTT), formulated by French bridge theoretician Jean-René Vernes in an article in The Bridge World in June, 1969 and popularized by Larry Cohen in his books, To Bid or Not to Bid (1992) and Following the Law (1994) is a theory that states:

“The number of tricks your side can take, if you play in your best trump suit, added to the number of tricks the opponents can take, if they play in their best trump suit, is approximately equal to the number of trumps held by both sides.”

The LoTT is known to systematically underestimate the total number of tricks when the total trump is high, there are double fits, or very pure suits. The final chapter of To Bid or Not to Bid discusses adjustments to make. Even with adjustments, the LoTT has also been criticized as simply inaccurate, most notably by Mike Lawrence and Anders Wirgren who wrote I Fought the Law of Total Tricks (2004). Nevertheless, the LoTT is often a useful guide for competitive bidding decisions.

The ACBLmerge report shows the number of total tricks, the number of total trump, and the difference between the two. If a side has more than one longest suit, the suit yielding the highest number of tricks is considered, the standard interpretation. If the LoTT were 100% accurate, the final number would always be zero. LoTT fans can see if they can justify the adjustment implied when the difference is not zero. Detractors can gloat when even with adjustments, the LoTT is significantly off.

7. Par Score and Contract(s)

The par score is the raw score for the contract beyond which neither side can bid further to improve the score for their side. The par score is shown from the perspective of N-S, i.e. it is negative if E-W are making a contract or N-S must sacrifice. There may be multiple par contracts which achieve the same score. For example, equivalently scoring contracts such as 4 and 4♠ will yield the same par score. Likewise 3N and 5♣/; however if the opponents can sacrifice profitably in say 4♠ but not 5♠ then only 5♣/ would be the par contract. All sacrifice contracts are doubled since that always improves the result for one side. As with makeable contract, there may be equivalently scoring sacrifices in more than one suit.

The par score calculation is computed from the double dummy information above and therefore carries the same caveats. Accordingly, some authors speak of the par presented here as “absolute par”, reserving the word par for the most realistic result given what each player knows as the hand is bid and played out.

Although par is a straightforward concept, there are some subtleties which the code must handle. First and rather rarely, neither side may have a makeable contract in which case the par score is 0 and the par contract is Pass. Second, and somewhat more commonly, both sides may be able to make 1NT from at least one seat. In game theory, this is a “hot” situation where victory goes to the side to get there first. This is situation indicated by ±1NT. In principle, this can even happen at higher levels. In Victor Mollo's Bridge in the Menagerie, Oscar the Owl, his chief kibitzer, remarks, “Curious hand, both sides can make four hearts”, one by drawing trump and establishing a side suit, the other by cashing outside winners and then crossruffing.

8. Copy-and-Paste Aid

Copying and pasting from a web browser is a treacherous affair. The results depend on your operating system, the web browser, and the target application, e.g. an e-mail program or Microsoft Word. If you copy a single hand from a board or copy the pair results, you will probably get what you expect. If you copy the entire board, you may not get what you want, especially in Firefox which seems to strip away all the formatting supplied by Cascading Style Sheets (CSS); IE7 seems to get this mostly right. Moreover, you may wish to have one or more hands in horizontal format or a pair of hands side by side in vertical format. To accommodate these needs, the copy-and-paste aid button will launch a pop-up window which presents the hands in various formats, ready to be copied-and-pasted as needed. It is impossible to anticipate every need, so please e-mail me if there is a format you desire.

Sophisticated users might ask why ACBLmerge does not provide a way to directly copy the exact HTML onto the clipboard at the press of a button. This because allowing web applications to write directly to the clipboard is a security hole. All serious web browsers either do not allow it at all or make it very difficult and even then still prompt the users to make sure they really want the data placed on the clipboard. Therefore, to accommodate a variety of operating systems and web browsers, it is best to simply have the user actively copy data to the clipboard.

It is possible that the Copy-and-Paste Aid popup window will be blocked by a pop-up blocker even though most pop-up blockers are now smart enough to distinguish between user launched pop-ups and automatically launched pop-ups. If this happens, you will need to edit your pop-up blocker settings or tell it to allow popups from If you save a results page to your local filesystem and open it from there and try to launch the Copy-and-Paste Aid from IE7, you will probably receive the message “To help protect your security, Internet Explorer has restricted this webpage from running scripts or ActiveX controls that could access your computer. Click here for options...” If you want to enable the Copy-and-Paste window to work from a local file, you will have to change the setting accordingly.