|
Matchpointer Online
|
|||||||||
|
Matchpointer Online :: Recent Matchpointer Articles
|
Recent Matchpointer ArticlesBelow are links to some articles which have either been printed in the Matchpointer print version, or appeared in the online version, or both. New articles intended to appear first in the next edition of the print version should be sent to Ben Takemori here. Articles intended for a more immediate publication in the online version should be sent to Bruce McIntyre here. Anything printed in the print version may appear later in the online version, and vice versa, unless the author requests otherwise. If you would like your article to appear online only after it appears in the print version, send it to both of us and I will arrange for this to happen.
Give Me A Hand from the "other" Vancouver by Joerg Schneider
Board 11 of the Monday Night Charity Pairs presented a problem both in bidding and in the play. I was East and my partner, Wanda Kellett, not surprisingly, sat West:
Our auction, with opponents silent, went:
Partner's 3♥ bid should be Kx -- with three she would have raised them directly -- and, unselfish as I am, I decided to let my partner play the hand. My (probably faulty) reasoning was that I had two honors in partner's suit and a singleton, so that a club ruff may well be our 12th trick. The opening lead was the king of clubs. How do you play it?
Partner won the ace, ruffed a club, cashed the ace of spades, came to hand with a heart, and cashed the king of spades, and when East showed out had two trump losers, the full deal being:
How good is this line? It succeeds if the queen is singleton or doubleton in either hand and when trumps split 3-2. I am no mathmatician but estimate it to be around 90%. The other line, which happens to work, is to win the ace of club and play a trump to the ten, and when it holds, cash the ace, come to hand with the heart and cash the king of spades, play a heart to the ace and pitch your losing club on a high heart. With that line you go down if the ten of spades loses to the singleton queen and a club comes back; now North, holding 987, would have a second trump trick; or, when South has four trumps -- so which line is better? I think that both are very close and in teams it may not matter much. However, in pairs there are many holdings where you can take all thirteen tricks when playing in hearts and taking only twelve tricks in spades would not give you a good score; and your best chance for thirteen tricks without endangering your contract is to take the first round spade finesse. Any views?
The last round in the Open Pairs on Friday night produced this oddity:
Each side bid and made 6♦, we on #29, they on #30! Our auction (sitting North-South on #29):
On the lead of the ace of diamonds and another diamond, declarer can establish the hearts using the spade honours as entries to lead a third heart and then to pull the last trump. A curious and rare occurance.
Short-Shorts by Greg Morse
Jeff Rubens, editor of the Bridge World, has just published a book, Expert Bridge Simplified (Arithmetic Shortcuts for Declarer). In it he covers a topic I have never see in print before; "What is the probablility that a defender is short in two suits?" He calls this the probability of a "short-short." Let's start with an example from The Encyclopedia of Play Techniques illustrating a technique called "Guillemard's Maneuver."
The defense start with three rounds of clubs, you ruff the third round. You have two red suit losers and must avoid one of them. Accordingly, you take the diamond finesse but it loses. You win the return and now must avoid a heart loser. If hearts are 3-3 there is no problem, but can you do better? Draw two rounds of trumps with the queen and ace, leaving one outstanding (Guillemard's Maneuver), cash the ace of diamonds, then play three rounds of hearts ending in hand. If the hearts are 3-3, draw the last trump and claim. If the hearts are 4-2 but the short hearts are with the short spades, you can ruff a heart in dummy for your tenth trick. Get back to your hand, and draw the last trump and claim. The chances of the spade-heart short-short are about 22%, and allowing for that adds approximately 7% to your overall chances (diamond finesse + hearts 3-3 + short-short = 50% + 50%x36% + 34%x22%). In the previous example you did not need to know the odds of the short short to recognize that Guillemard's Maneuver was an additional chance that could never cost and might gain. But sometimes the choice is between playing for a short-short or taking a finesse. Here is an example from Bill Root's How to Play a Bridge Hand:
They lead the king of hearts. There is no reason to hold up so you win the ace. If the spade finesse works, you can draw trump and run the clubs for twelve tricks. If it doesn't, they will cash two hearts and a diamond and you will be one down. Is there anything else? You cash the ace and king of spades, then, if the queen has not dropped, play on clubs, throwing hearts from your hand. If the defender with the short clubs also has the short spades, you can throw at least one heart loser, limiting your losers to a spade, a diamond and a heart. What are the odds? The odds that the queen of spades will drop singleton or doubleton are about 33% and the odds of the club-spade short-short are about 40% giving you an overall success rate of: 40% + 60%x33% or about 60%. Clearly this is better than the finesse and is the recommended line of play.
A final example comes from Rubens' book itself. This one involves comparing two possible short-shorts.
They lead the ace of spades which you ruff. All will be well if the clubs are 3-3. There are two additional possibilities: Line 1. Draw one round of trumps, then try for a club ruff in dummy. This needs hearts to be 3-1 or 4-0, and if clubs are not 3-3 then the short heart must be in the same hand as the short clubs, about a 12% chance. Line 2. Try for a diamond-club squeeze. Ruff the opening lead and play all the hearts then the AKQ of clubs, hoping that the short clubs are with the short diamonds, a 22% chance. So the squeeze is the better play (and surely more fun!)
Summary Where do the numbers 40%, 22%, 12% etc., used in the above examples, come from? For a full explanation, see chapter 7 in Rubens' book. Briefly and somewhat simplified, we can say that short-shorts come in three different kinds, depending on how many cards (called Remainders) the opponents hold in the two suits. If we have eight cards in the trump suit, the Remainder is 5. If we have a nine-card fit the Remainder is 4. The probability of a short-short depends on whether the Remainders are Even or Odd. The three cases are: Odd - Odd, Odd - Even and Even - Even. The probabilites of the short-shorts (for Remainders in the range of 4-8) are: Odd - Odd = 40%, Odd - Even = 22%, Even - Even = 12%. For Remainders of exactly 3, add 3% to the above numbers so: 3 - 3 = 46%, 3 - Odd = 43% and 3 - Even = 25%. Therefore, to cover most of the cases of short-shorts you only need to remember 4 numbers: 40 - 22 - 12 - 3. Since Remainders of 1 and 2 are important special cases, Jeff has calculated them separately. (He does not say how.) For those of you who are keen, here is a more complete table, somewhat simplified and rounded off, derived from the numbers in Jeff's book.
Sectional Flyers Editorial by McBruce ... and therefore not necessarily an opinion held by Unit 430
I've been preparing the Unit's sectional flyers for many years now. When you're about to print 500 or 1000 copies of something and then send it all around, you need to be sure that everything on it is correct. One thing I have not been able to understand is why the tournament flyers are so important to people. Until recently, I printed flyers on one side of a sheet of paper. Directing at the club taught me the error of my ways there: bridge players found the flyers more useful for jotting down bridge hands on the conveniently blank reverse side, and then leaving them at the table or on the floor. Not a great use of the Unit's funds. So I split each flyer in half and printed them on paper half the size, using both sides. The grumbling was immediate. "I liked the old flyers better." Really? Why? "They, well, I don't know, the new ones are different?" Only in that you have to turn them over to read all the information. "Maybe that's it." Well, sorry about that. Nobody wants to say that the real reason they don't like the smaller flyers is that they can't write on the back. It's not as though there isn't plenty of scrap paper at any bridge club produced daily. About a year ago, people began to get antsy about having the flyers posted on the ACBL website. Discussions would go something like this: "I can't find the tournament on the ACBL site." You mean the listing of sectional tournaments on acbl.org? It's certainly on the list; the sanction has been obtained. "No, it's the flyer I need." The tournament is six months away. Why do you need a flyer now? "So I can plan my bridge." Well, the dates are set. What else do you need? "Well, I need to find out what events start at what times." For a tournament six months away? My, my, you certainly are organized. Isn't it enough to write down "bridge tournament" and reserve the afternoon and evening now and then work out the dates later? "Well, I need to know where it is and what events are happening." Does that matter so much, six months in advance? "It does to me." Well, if it is that important to you, the information is available at matchpointer.com. "I know, but I want to get it on ACBL.org. Why can't it be there now?" Before I tell you the reason, can I just suggest something? It's bridge. You like bridge. So come out and play already, and quit trying to find reasons not to! If you and your partner play well, you'll win some masterpoints. If you don't, you'll still have some fun, meet some other people that enjoy bridge and perhaps even learn a few things from your mistakes. It really shouldn't matter whether it's teams or pairs, or whether the strat limits put you at the top or the bottom of a strat, or whether the start time or the break time is your own personal preference. It's bridge. The dates are out there; the start times are there too. A flyer is not an invitation: tournaments are open to anyone who wants to play bridge. Prove that you do like bridge and come out and play! Now, here's why flyers for tournaments down the road don't appear too early. We've tried it and it causes trouble. People looking for a local tournament flyer tend to stop, snatch and go when they think they've found it. If it is an April Regional and they see a flyer for a Vancouver tournament in September, they grab it, and as they leave, it registers with them that there is no other local tournament until then. A few weeks later, they hear their friends talking about that wild hand at the sectional and realize that they've missed one. The flyer for the May sectional was probably inches away from the September one, but once you find what you're looking for, you don't look that closely at anything else. It happened several times a year when I tried putting two out at once. So we don't anymore, but we do try to put the dates of following tournaments on flyers. (Don't even suggest putting the dates of PREVIOUS tournaments on flyers. That would be silly.) If you do need details about tournaments quite some time in advance, the place to go is matchpointer.com. At the tournaments page you will find a flyer for the next open sectional in pdf format for printing, but you can view basic text pages with information about the tournaments further on down the road. These text only pages often give even more information than the flyer provides, such as transit routes, nearby restaurants and shopping, and extra details on the events at the tournament. By the way, sectional starting times are fairly standard and have been for almost a decade, with one key change for 2010. Friday games begin at 1:30 (so you can take a half-day off work and make it for the Friday afternoon session), and 7:30 (for those who need to work the whole day). Swiss Teams on the last day of the tournament begin at 10am (a change from 10:30am in 2009) and the second session depends on the attendance and the format chosen by the Director. The middle day starting times are 1:00pm and 6:30pm (so that you can get home earlier and have a bit extra sleep before the early Swiss Teams start). The single exception to the 1:00/6:30 middle day start times is that on Saturday at the Victoria Day Sectional, the second session starts at 7:00pm, because the Unit's Annual General Meeting begins after the afternoon session. An extra half hour is given so that people attending the meeting don't sacrifice too much of their dinner time for it.
Night and Day by McBruce
Recently at the VBC we ran an ACBL-wide Inter Club Championship. This event is held several times a month on a specified Monday, Tuesday, Wednesday or Thursday session. Ours was a Wednesday evening game. All participating clubs play the same boards, and the results are scored normally at the club for a small masterpoint bonus, then sent to Memphis where the results from all clubs are matchpointed together and the ACBL-wide overall pairs get a larger masterpoint award. All this costs just an extra dollar per player. In our recent ICC game we had 11 tables and the day after the game I checked the results from other clubs on the ACBL website, to see if any of our players had made the ACBL-wide overalls. The ICC games are not very actively promoted by the ACBL. There is a web page for the games, but nothing in the Bulletin. It's a good concept, but it's always hard to explain to players that their 63% game at the club translated to a 61% game when matchpointed against other clubs. (Most scores tend to push back towards average when scored across a larger field, although a few do go further from average!) On the night in question, there were about 18 clubs in the ACBL that ran the game. And to my surprise, ours was the only game that ran a Mitchell movement! All of the other games were Howell movement games, none coming even close to our 11-table turnout. Think, if you've played this long, about the past 25 years in club bridge. Since my novice days of 1984, we have seen these major changes:
But the biggest change since 1984 is neither related nor caused by any of these. In the past 25 years, there has been a complete reversal in attendance trends. In 1984 we struggled to keep our morning and afternoon games afloat. Now it is the evening games that we struggle to fill. It's not a sign of trouble in the bridge world: the rise in morning and afternoon games has been greater than the losses at evening games. A few evening games that were around in 1984 have gone, but most are still here, just a little smaller. In a daytime game, you're not as pressed for time as you are in an evening game, where a break for a snack means people get out at a fairly late hour. We're a lot more concerned with the evening end time in 2009. Past issues of the Matchpointer show that the normal time to start an evening game on a weeknight in the 1970s was often as late as 8pm! But if the day game drags and takes a half an hour longer, it's not such a big deal. Another factor must be more duplicate players not working 9-5 jobs. In the mid-1980s I worked an afternoon shift for several years and played very seldom at clubs. I could easily have played a day game or two, but they weren't as big as they are now. We're still not attracting enough new players to our game to offset the fact that as a group, we continue to get older. We retire and switch to playing daytime games. (If you want to see the newest eager players, come out to an evening game!). Change is not always a bad thing. There has been an overall increase in tables as clubs adapt to the new attendance trends. And now, starting with the next Vancouver Regional in April 2012, tournament schedules are beginning to adapt. Start times at the 2012 Vancouver Regional will be 10am, 3pm, and 7:30pm. It's almost the same schedule as before, turned upside-down:
And already people who hear about this change are bleating "I won't come." Yes, you will. Look again at the list of changes above. There isn't a single one of them that hasn't been considered without somebody saying "I won't come." And sometimes they don't, but it doesn't matter, because the extra people that do come because the change has been made make the naysayers absence insignificant. Most of the angry people decide eventually to come back. Those that don't we can usually do without. Can anyone think of a single player who completely quit playing bridge when the Unit decided to have no smoking at sectionals? I was there at the Unit's annual general meeting when it happened and there was a full room of people, almost half of whom railed about how they and their many, many friends would stop coming to tournaments, and the Unit would be broke in a year or two. Most of them continued to play and learned to make crucial cardplay decisions without first taking a long drag. Those of us who won the vote by a slim margin said very little, but knew that we wanted to be able to see the ceiling at the end of a tournament. (In the end it wouldn't have mattered how the vote went; only a few years later we would have been unable to rent a tournament site that allowed indoor smoking anyhow.) Under the 10-3-7:30 system, we are going to be able to play the two main sessions each day with about 60-90 minutes between sessions for a short mid-afternoon snack, and we'll be done early enough to see a movie in the evening, or possibly even a double feature. We'll be able to have a nice breakfast before the game without getting up at some hopelessly early hour. For those working during the day, there will be events in the evening sessions that they can play. And for people who want to play three sessions a day, it will be no more difficult than before. You're going to love it. I know I will. Think of what this means for Daily Bulletin production at Regionals. Probably 70% or more of the tournament's table count will be in the 10am and 3pm sessions. The evening sessions will have decent attendance but won't be nearly as high as the main events during the day. But at 8pm each night I can begin processing the days events, knowing at that point the attendance in the evening events, and how much Bulletin space will be needed for them. By the time the evening session ends I can have everything in place except for the evening events, which can be very quickly added. I may even be able to sleep enough to get to play during the day! But it will be the Spring of 2012 before this all takes place. DINO is willing to try it, but only as a test. We need to convince DINO that this is the way of the future with a big attendance in 2012. So, when the tournament flyers start appearing for the 2012 Vancouver Regional, try, just this once, not to do what bridge players do too often -- complaining about changes to their routine -- but instead try to see that there is a trend that we need to follow, and it's not too difficult to do so.
Why I Use Arrow Switches by McBruce
Most everyone by now has seen them in games that I run. In the last round of a three or four-board game, or the last two rounds of a two-board game, we twist the boards 90 degrees, so that the North-South pair gets the East-West cards, and vice versa. And players who haven't seen this before (or some who have and don't quite get it) often ask me why I do it. The short answer is this: it allows us to determine a single winner more fairly than simply comparing the best East-West score and the best North-South score. The next question is invariably "why are only a few rounds switched? Shouldn't we switch more?" And at this point, I usually can't respond right away because you really do need to start playing the boards or you'll be finishing several minutes after everyone else, delaying the scoring and keeping people at the club later than they want to be. But the answer from the mathematicians is that switching about 12.5% (one-eighth) of the rounds is the best technically: and from this the standard procedure (in places that use arrow switches: which is pretty much everywhere outside the ACBL) is to switch two rounds in a 12 or 13 round game of two boards per round (2/13 is closer to 1/8 than 1/13), and one round in a game with eleven rounds or less. That's it in a nutshell. Of course, just like computer hands vs player-dealt hands, or limited conventions vs use-whatever-you-want, or Howell vs Mitchell, or spoken bidding vs bid-boxes, bridge players are conditioned to find a reason to believe that the arrow switch procedure has personally screwed them, and the nutshell argument will never convince them otherwise. So let's go into this further: For three seasons ending in 2008, the National Hockey League ran a schedule for its six five-team divisions which called for division opponents to meet eight times a season, four times in each city. During this time, the Detroit Red Wings were the best team in the West and clinched the top seed each year by a dozen points or more. They were good but not that good: their totals were inflated by the benefits of playing in a division with four teams that at that time were quite weak: Chicago, St. Louis, Nashville, and Columbus. In the same period, the division our local team played in was a five-team division where all five teams might conceivably win in any year. The best team in a tough division will naturally get less points from its divisional games than a dominant team in a weak division. If an NHL schedule has a lot of divisional games, the dominant team can get an advantage of 10-15 points over other division leaders just because their divisional opponents are weaker. Are they really that good? Not always: in 2006, the Wings had the best record in the league yet lost to the Oilers in the first round, a team that barely made the playoffs. In duplicate pairs, the same sort of thing happens in every tournament. We try as Directors to keep North-South and East-West fields balanced, but it's a nearly impossible task for several reasons. The majority of players, especially for evening sessions, tend to arrive in the final ten minutes before game time, some with strong expectations of getting a North-South seat. Even if the masterpoints are balanced, we all know that masterpoints isn't everything and some under 1000 pairs can be expected to finish higher than some pairs over 2000. And quite often, a few unexpectedly good (or bad) games by a few pairs in the same direction will make the field seem to be skewed, even though it really isn't. At a recent sectional, a player approached me and complained that a majority of the overalls were in one of the three sections of a pairs game. Until Directors are able to look ahead in a time machine to see who is going to play above or below their expected level, this is going to be a possible result, even in a field that looks balanced when the game starts. The notion that your score depends to any great extent upon who you play against is at least 95% bunk. In a Matchpointer article in 2003 I examined a 21-table Monthly Unit Game where the top eight pairs overall were from Section B. By assigning an estimated final score to each pair based on their perceived strength, I showed that Section A was at a slight disadvantage that night, mostly because the field had been seeded for equal numbers of pairs in each flight, but the best A pairs were all in the same section/direction. However, further analysis showed that the overall winners had virtually no advantage from seeding, and simply played far better than predicted. The conclusion was that your final score depends on your established playing level (strength), a combination of luck and skill that allows you to play above or below your playing level for that session (form), and the advantages and disadvantages of the movement (chance). Looking at each pair's list of opponents and their expected score on each round, we determined that strength is the main factor, and form is the secondary factor. Chance is quite minor, accounting for only 3% of effect on the final scores. What matters is the established skill level of a pair and how well you play that night. But that's not what players want to hear. Players who have played below their expected level (especially those whose partners have played below their expected level) are quick to seek out an excuse that is easier to swallow than "we made too many mistakes." A look at the seeding is a ready-made excuse, and I have heard some amazing statement in support of these excuses: "this pair shouldn't really be in flight A" (they each have over 5,000 masterpoints) is the general form. But also, a movement that players are not familiar with and do not understand, like an arrow-switch, is another ready-made excuse. Here are some things to remember about arrow switches that people ask about: sometimes I can explain them reasonably well, other times I am busy and cannot give the explanation the care it deserves:
In fact, the best positive comment about arrow switches is this very simple one: it's a way to go home knowing that you are (or someone else is) the one and only winner. Imagine a 10-table Mitchell, nine rounds with a skip, you're East-West. At the end, you win the E-W field with a 61.4% game. The pair you skipped has won the N-S field with a 61.6% game. You didn't play against them and you sat in a different direction from them on every single board, so there was no way for you to directly affect their score, and vice versa. There's no way to tell whether their 61.6% is a better game than your 61.4%: it's like comparing apples with oranges, as they say in algebra. Yet if this is a club championship game or a Unit Game, the N-S pair you never got a chance to play is going to win significantly more masterpoints for their "overall" win. If it's a Side Game at a Regional, the masterpoint award difference could be one or two points, possibly gold points! Yet this overall win is about as statistically significant as the Florida results were on election night in 2000. An arrow switch in the final round improves the balance quite a bit and probably makes the overall result ten times more significant. Not to mention that it is more natural to announce a single winner in any competitive game. Imagine if they played the Stanley Cup Playoffs down to an Eastern Conference winner and a Western Conference winner and just quit at that point, or maybe had some sportswriters award the Stanley Cup to the survivor they figured was best. That would be (unless you like the current college football system) ludicrous. One winner games just make more sense.
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||