3rd Belgian Championship 3-Point Matches

Dear backgammon friends,

BGFed.be kindly invites you to the 3rd Belgium Championship 3-point matches, at least 14 rounds, on Saturday the 9th of February 2019, in the Arena, avenue Pasteur 2A – 1300 Wavre, very easy parking. See all info on the included flyers [ EN | NL | FR ].

9.15 hours : registration & breakfast ;
10.00 hours : presumably Swiss movement tournament ;
+/- 14.00 hours : light lunch ;
+/- 21.15 hours : finals, cocktail drink, proclamation & prize-giving ceremony.

Please, mandatory registration before Thursday the 7th of February and BYOB (try to bring a board and a clock).

Already registered : Brisaert Johan, De Weert Kristoffer, Van Middelem Guy

Come & join us, we expect a thrilling tourney !

Hope to see you then,
— Guy

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3rd BMS Xmas Trophy won by Ronny Conaert (result) and Michel Lamote (PR). Now with complete PR ranking.

On Saturday 29 December 2018, fourteen players competed in the Sandeman Club in Gent for the 3rd BMS Xmas Trophy. Almost the complete top-12 of the BMS  Grading Table was present to try and play as best they could.

After 5 rounds of play (9-point matches), Ronny Conaert was the last man standing with 5 victories, followed by Geert Van der Stricht and Johan Huyck with 4 wins:

Ronny with the Xmas Trophy (l) is congratulated by organiser Geert (r) (photo : Robin Bilderbeek)

Ronny has been a dedicated backgammon student and expert player  for years. Recently he has upped his efforts to improve by playing challenging Master Series against strong opposition. On Saturday, he proved his mettle by winning five medium-length matches in a row, showing stamina and will to win. Congratulations, Ronny!

The Xmas Trophy is also a BMS event. All 35 matches are recorded and XG-transcribed.  In this contest, Michel Lamote came out on top. Geert Van der Stricht and Marc Van Damme also managed to play below-5:

PR 1. Michel (5 x 9). Scores 2/5.

PR  2. Geert (5 x 9). Scores 4/5.

PR  3. Marc (5 x 9). Scores 2/5.

A good PR not only depends on skill, but also on circumstantial luck. There are easy matches and difficult ones, matches with a high DD (= degree of difficulty) and with a low DD. If you have the bad luck of finding yourself in backgames or notoriously difficult prime-vs-prime positions, you may well see your PR deteriorate quickly. This may explain  the reverse order of this top-3, where Michel played 0,5 PR better  and Marc 0,5 PR worse than their true PR.

Just behind this trio come 4. Misja Alma (N) (PR 5,06) and 5. Tilman Söhnchen (GER) (PR 5,16).

Then we find the four players who occupy places 4 to 7 on the BMS GT: 6. Paulus Van Rooijen (N) (PR 5,65), 7. Johan Segers (PR 5,70), 8. Paul Van Dijke (N) (PR 5,90) and 9. Johan Huyck (PR 5,91). These are excellent PRs by all four, indicative of significant progress and sustained focus on the day.

Also 10. Luc Palmans (PR 6,53) and 11. Ronny Conaert (PR 6,96) did not disappoint and can be proud of their performance. 12. Guy Van Middelem (PR 7,92) comfortably played at par, but somehow seems to have missed an opportunity to excel.

13. Robin Bilderbeek (N) (PR 8,70) appears to be the only player in the field who  failed to impress. Robin certainly made progress in recent months, but could not find his best form.

14. Steven Hoeylaerts (PR 9,39) certainly deserves praise for this performance. Having picked up the game less than a year ago, his learning curve has been steep and this below-10 PR is proof of that.

All in all, this field of ambitious students of the game played extremely well, achieving an average PR of 6,16 (35 x 13). Belgium’s top-3 were able to stave off a valiant assault by two accomplished Dutch and German competitors as well as by their four closest pursuers on the BMS GT. Below them, Luc, Ronny and the others confidently consolidated their top-10 status. Check the BMS GT in the black banner above to see the current standings.

The event was a great success. Guy Van Middelem, President of BgFed.be, thanked Geert, Johan Huyck and Paulus Van Rooijen for the hard work and magnanimously called the organsition “perfect”. That was the sign for all present to move from the  playing room to the more dyonisian bar area, where many a word was said in jest and otherwise…

 

 

 

 

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Correction rating formula

A few days ago, it was pointed out to me that the Elo-based formula used to calculate the rating list was implemented incorrectly. This mistake has now been corrected. The result is major shift in the ratings.

I sincere apologize for the error, for which I take full responsibility. I also thank the person who has kindly pointed out the error to me.

The error and its consequences

My programming error was that the match length was not taken into account when calculating the winning chances of the two players. In other words, the winning chances were calculated as if each match were a 1-point match. This error gave an unfair advantage to the players with a high rating and a disadvantage to the players with a low rating. The ratings on top of the list were thus too high, and the ratings on the bottom of the list too low.

To understand why, remember that the longer match, the higher the winning chances of the rating favourite. The greater your winning chances, the fewer rating points you gain when you win and the more points you lose when you lose.

However, by treating each match incorrectly as a 1-pointer, the winning chances of the rating favourite were underestimated. If the rating favourite then actually won the match, her rating went up by too much. But if she lost the match, her rating went down by too little. Similarly, if the rating underdog won the match, she did not receive the rating increment she actually deserved, while she was punished too much in case of a defeat.

Technical explanation

The correct formula for a player’s winning chances P is to be found on http://www.bkgm.com/faq/Ratings.html#what_are_my_chances_of_winning_:

P = 1 / (1 + 10^(- D * sqrt(N) / 2000))

D is the difference between the player’s rating and her opponent’s rating, while N is the match length.

In the software I wrote, I had forgotten the sqrt(N) on the right-hand side in the definition of P.

Correction

To rectify things, a choice had to be made between two options:

  1. The ratings are recalculated using the correct formula for all matches in the database.
  2. The correct formula only takes effect for matches played on or after a specific date, while for matches before that date, the incorrect formula is maintained.

After discussion with BGFed.be president Guy Van Middelem and with former rating committee member Luc Palmans, it was decided unanimously to opt for the first possibility. I would like to thank Guy and Luc for their kind advice and their understanding.

The result of the correction is major change in the rating list. A large bonus for some, an equally large discount for some other.

Once more, I am extremely sorry for the mistake, which is mine and mine alone. To the best of my knowledge, the ratings are now correct.

Should you wish to have more explanations, please do not hesitate to contact me by phone or by email. If there is anything else I can do, just let me know.

— Johan Segers

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Johan Huyck (Gent BC) wins high-quality BIC Final.

The 2018 BIC Final between Johan Huyck and Paul Van Dijke (Brugge BC) started punctually at 6 PM. Johan won the first 13-pointer quite easily with a 7+ luck rate and an astonishing below-3 PR, but Paul managed to win the second match to draw level. The  third and decisive 13-pointer was again a one-sided affair with Johan coming out on top.

Johan (l) and Paul (r) before start of play. XG transcriber Robin can be detected in the background.

The encounter was filmed and transmitted on a screen in the adjoining bridge playing room, with commentaries by Geert Van der Stricht, Marc Van Damme, Paulus Van Rooijen and myself. Robin Bilderbeek transcribed live so the spectators (all five of them…) could enjoy immediate feedback by the computer programme Xtreme Gammon. To everybody’s astonishment, both players rose to the occasion and found their best playing skills. Here are their excellent PR’s :

PR Johan (3 x 13). Johan wins 2-1.

PR Paul (3 x 13). Paul loses 1-2.

Congrats to both for a well-played, high-level match. A video of the complete final (with XG and commentary) will soon be made available on YouTube thanks to the dedication and efforts of Robin Bilderbeek.

Johan presenting the 2018 BIC trophy.

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Johan Huyck and Paul Van Dijke play BIC Final on Friday 21 December in Gent.

(Image made by: Robin Bilderbeek)

For the second time in two years, Johan Huyck (Gent BC) has reached the final of the BIC competition. Last year he lost to current BIC Champion Metin Ates, but he gets a second chance to take the title this year. His opponent is Paul Van Dijke (Brugge BC), who made it to the final after a long campaign which started in Division II.

The match will be played on Friday 21 December at the Sandeman in Gent. The first player to win two 13-point matches will be crowned BIC Champion 2018. Start of play is   6 PM. The players will play in the bar area and the match will be transmitted on a semi-large screen in the bridge area. Robin Bilderbeek will do live XG transcribing and the action will be commentated on by Michel Lamote, with Geert Van  der Stricht and Marc Van Damme as guest commentators.

Everybody is welcome to come and witness the climax of this prestigious competition. All spectators will have to take a seat in the bridge area, as no kibitzers will be allowed in the playing area. Income is free.

 

 

 

 

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Minutes General Assembly BGFed.be npo 7-Dec-2018

The minutes of the most recent general assembly of the BGFed.be npo can be found on the page Federation. Some other stuff on that page has been updated as well.

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BIC 2019

The rules of the Belgian Individual Championship (BIC) 2019 can be found in the menu via BIC > BIC 2019.

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Update rating list: two-week period

It seems that last weekend, I’ve forgotten to update the rating list. My apologies. This weekend’s update therefore concerns a two-week period, taking into account matches played between Monday, November 26 and Sunday, December 9, 2018. — JS.

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BMS : Master Series 0062 and 0064 wrapped up.

In a continued effort to improve their game, Geert Van der Stricht, Johan Huyck, Robin Bilderbeek and Michel Lamote played, recorded and transcribed ten 13-point matches. Over the past years it has become clear that PR’s achieved in Master Series of that length do not deviate much from the players’ actual playing strengths and thus provide a good indication of where they stand as far as intrinsic skill is concerned :

PR Geert (10*13). MS1 0064 is drawn 5-5.

PR Johan (10*13). MS1 0064 is drawn 5-5.

PR Robin (10*13). MS1 0062 is drawn 5-5.

PR Michel (10*13). MS1 0062 is drawn 5-5.

Encourageing PR’s by all four players. Geert (3), Johan (4) and Michel (2) solidify their BMS ranking, while Robin (9) is edging closer to below-7 status.

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4 Cubes 2018 – Leuven 2 keeps the trophy (again)

Geert (Gent) shaking hands with Odette (Leuven 1). Their match was one of the nine matches between their two teams in the final round of the 4 Cubes 2018, the Belgian backgammon team competition.

All six teams came together to play the last of five rounds of the 4 Cubes 2018, the team competition organized by BGFed.be. In the tennis club Longchamp in Uccle, Brussels 2 met Leuven 2, Leuven 1 met Gent, and Brugge met Brussels 1. The main area and the room upstairs were packed with backgammon sets, some cheap and some luxury, clocks, and recording equipment. Players from all over the country (and even from across the border) enjoyed an evening of playing and camaraderie, until the late hours.

The encounter between Brussels 2 and Leuven 2 was the de facto final of the competition: the winner of the encounter would be first in the final ranking and earn the right to hold and display the precious 4 Cubes trophy throughout 2019. Around midnight, it was Leuven 2 that came out on top. Congratulations for the team, who already won the 2016 and 2017 editions. Full results can be found in the Tournament Book.

We would like to thank all players and team captains for their participation, sportsmanship, and fair play. Fixing dates and motivating players was not always an easy task, but some team captains showed remarkable patience and gentlemanship. The organizing committee has listened carefully to the feedback and suggestions formulated by the captains and will soon come up with a proposal for the 2019 edition.

Keep on rolling!

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