From ArimaaWiki

The 2009 World Championship began with the Open Classic on Thursday January 8, 2009:

• 2009 Open Classic Round 1
• 2009 Open Classic Round 2
• 2009 Open Classic Round 3
• 2009 Open Classic Round 4
• 2009 Open Classic Round 5
• 2009 World Championship Finals, Rounds 1-2
• 2009 World Championship Finals, Rounds 3+
• 2009 Arimaa Championship Final Game

For other events see Event Reports

Contents 1 Pre-Tournament Analysis 2 Post-Open Classic Analysis 3 Post-Tournament Summary 4 Open Classic Final Standings 5 World Championship Final Standings

Pre-Tournament Analysis

Eighteen players have registered for the 2009 Arimaa World Championship, down from twenty-six last year. However, nine countries are represented, just as many as last year, so the international flavor of the tournament hasn't changed a bit.

The tournament format remains the same as in 2008, with a Swiss preliminary to narrow the field to eight finalists. A few accomplished players did not register this year, perhaps reflecting their pessimism about qualifying among the top eight. According to the tournament rules, if eight or fewer players registered for the Arimaa World Championship, there would be no preliminary rounds, and we would skip straight to the finals. Will there come a day when the eight top players self-select? I doubt it. As long as the championship remains an open tournament rather than being invitation-only, people will want to take a shot at the glory.

The Arimaa game room as a whole saw increased participation year over year, with more games played than ever before. Paradoxically, the maturing of the Arimaa community may have contributed to the decreased registration for the World Championship. 2008 saw the introduction of the live Continuous Tournament in the off-season, so for the first time the World Championship is not the only live tournament available all year, and thus not the only outlet for tournament-hungry players. In the future, having more casual events throughout the year will presumably narrow the focus of the Arimaa World Championship down to crowning the best player.

Fourteen of 2009 field also participated in last year's World Championship, an increase from twelve returning players then. The average increase in rating among the returning players is 16 points, down from year-on-year increases of around 100 points in past years. This is probably due to changes to the handling of provisional ratings which were instituted to combat rating inflation. In the opinion of your humble author, the anti-inflationary measures have actually caused a bit of deflation. The players have improved from last year, but the ratings clamp-down prevents the numbers from showing it.

Among the returning players are 99of9, naveed, and omar, seeded fourth, seventh, and eighth, respectively. These three are the only ones to have participated in all six Arimaa World Championships so far, and every year they are contenders, including last year when all of them qualified for the finals

The top two seeds this year are chessandgo and Fritzlein, just like last year when they finished second and first. Conventional wisdom is predicting that that one of them will be champion again this year, which brings back memories of the 2006 World Championship. At that time the top two seeds Fritzlein and 99of9 were given a combined winning chance of over 80%, both by simulations and by conventional wisdom. As fate would have it, neither of them finished among the top three! (KJ)

Post-Open Classic Analysis

The Open Classic wrapped up on Sunday, February 8, with a full slate of games. There were relatively few "upsets" during the tournament, and all of the top six pre-tournament seeds have qualified for the Finals. There were some surprises, however, as Camelback and Tuks (ranked 9 and 10, respectively pre-tournament), jumped ahead of Naveed and Omar to grab the last two positions. Their reward: being matched up against the top two players in the first round of the finals.

Chessandgo grabbed the top spot with a perfect 5-0 record while Fritzlein, the defending champion, nabbed the second seed. All of Fritzlein’s opponents had 3 or more wins, giving him an impressive Strength of Schedule score of 18! Arimaa_master jumped three spots from his pre-tournament position, up to #3. The 4th and 5th place finishers, 99of9 and Adanac will meet in the first round of the finals and the #6 seed, The_Jeh, will have a re-match against arimaa_master – the only one of the four upcoming first round games that is a re-match from the Open Classic.

Post-Tournament Summary

There were no undefeated players in the 2009 World Championship and the title game down to a single winner-take-all matchup. Jean Daligault (chessandgo) triumphed over Karl "Fritz" Juhnke (Fritzlein) to win his second World Championship, the other coming in 2007. Daligault and Juhnke now share the distinction of being the only repeat champions. The tournament was noteworthy for many exciting games, but relatively few upsets. With the first ever Arimaa sets scheduled to be produced in 2009, it can be hoped and expected that far more players will participate in the 2010 World Championship.

Open Classic Final Standings

World Championship Final Standings

Seed	Participant	Name	Rd. 1	Rd. 2	Rd. 3	Rd. 4	Rd. 5	Rd. 6	W-L	Finish
1	chessandgo	Jean Daligault	S 8 W	S 5 W	G 2 L	G 4 W	bye	S 2 W	4-1	1st
2	Fritzlein	Karl Juhnke	G 7 W	S 3 W	S 1 W	G 5 L	S 5 W	G 1 L	4-2	2nd
3	arimaa_master	Jan Macura	S 6 W	G 2 L	S 5 L				1-2	t-5th
4	99of9	Toby Hudson	G 5 L	G 8 W	S 6 W	S 1 L			2-2	4th
5	Adanac	Greg Magne	S 4 W	G 1 L	G 3 W	S 2 W	G 2 L		3-2	3rd
6	The_Jeh	John Herr	G 3 L	S 7 W	G 4 L				1-2	t-5th
7	Tuks	Louis-Daniel Scott	S 2 L	G 6 L					0-2	t-7th
8	camelback	Tholkappian Chidambaram	G 1 L	S 4 L					0-2	t-7th