2007-2010 cycle was influenced by complications that arose with re-unification of the title in 2006.

After more then a decade of schism, the two world champions ("classical" champion Vladimir Kramnik, and FIDE champion Veselin Topalov) finally agreed to re-unite the chess crown. However the 2005-2007 cycle (without Kramnik) was already on the way, with Topalov as the then reigning FIDE champion automatically seeded into the final tournament. Instead of modifying the cycle by putting the runner-up into candidates or even directly into the final tournament (like it used to be done in the past) they decided that the runner-up will be eliminated from the whole cycle.

Kramnik eventually won the controversial match (known as "Toiletgate") in the tie-breaks and Topalov was out of the whole cycle. However at that time Topalov still had a chance to fight for the title outside the cycle - there was a rule where any former World Champion or +2700 rated player can challenge the reigning Champion and if he can guarantee a 1 milion USD prize fund, the Champion can not decline the challenge! Soon after losing the 2006 World championship match Topalov made the required 1 milion USD challenge. FIDE turned down the challenge on technicality that the money guarantee was from the "wrong" bank. Topalov challenged again, this time with guarantees from the "right" bank. Kramnik had no intention to play Topalov so soon again so they dragged out their official reply as long as they could. Since the World Championship in Mexico was already half a year away the challenge was then officially turned down by FIDE. At the same time FIDE scrapped that "1 milion dollar" rule. So Topalov was definately out of the race.

In the meantime Kramnik wasn't satisfied with his status either. He wasn't satisfied that the next World Championship is a tournament and not a match. There was a possibilty that he will boycott the tournament. So he bargained out that in case he is not victorious in Mexico, he gets a "re-match" with the winner. Topalov's camp raised their voices so they bargained out special privilegies for Topalov in the next 2007-2010 cycle.

FIDE issued the following rules:

• If the winner of the WCCT 2007 in Mexico is any player other than GM Vladimir Kramnik, then a World Championship match of 12 games will be held within the period May-September 2008 between the reigning World Champion (winner of WCCT 2007) and the then previous World Champion GM Vladimir Kramnik (match A). The minimum net prize fund will be 1,000,000 USD. At the same year 2008, and after match A, the winner of the World Cup 2007 will play a challengers match of 8 games against GM Veselin Topalov with a minimum net prize fund of 150,000 USD (match B). In 2009 (within the first six months) a World Championship match will be held between the reigning World Champion (winner of match A) and the winner of match B. 
• If the winner of the WCCT 2007 in Mexico is GM Vladimir Kramnik, then a World Championship match of 12 games Kramnik - Topalov will be held within the period May-September 2008. The minimum net prize fund will be 1,000,000 USD. In 2009 (within the first six months) the winner of the World Cup 2007 will play a World Championship match of 12 games against the winner of the World Championship match 2008 Kramnik - Topalov.

World Championship tournament in Mexico was won by Viswanathan Anand, so the first option kicked in - Anand had to play a "re-match" against Kramnik, while Topalov had to play against winner of World Cup 2007.

2007 World Cup and the following negotiations

In December 2007 Gata Kamsky won the 2007 World Cup (download games here). While Anand and Kramnik quickly agreed to play their World Championship match in October 2008, there were many complications with Topalov-Kamsky Challenger match. The original deadline to chose the organizer for Challenger match was end of January 2008. Only Bulgarians made a bid to organize the match. Kamsky didn't want to play in Bulgaria so he complained that he had only one month to find potential sponsors, while Topalov had at least 4 months, and made a (reasonable) request to extend the deadline. FIDE granted and the dealine was extended for almost 3 months. Right decision in my opinion.

But here is where the story gets ridiculous. Even after the extension there was still only one bid - Bulgaria. Kamsky's manager Alexander Chernenko played a strange game with "phantom" organizers all over the world. With every new set deadline (there were some 5 or 6 further extensions) his answer was always that everything is already set and that "the check is in mail". It was getting beyond ridiculous, best described with these word's from Mig Greengard:

"Chessbase is saying Yuri Vasiliev is saying that Kamsky's manager Alexander Chernenko is saying that the FIDE bank in Lausanne is saying that the money from the Ukrainian organizers for the Kamsky-Topalov candidates match has arrived."

And the designated dates for the match were getting closer and closer. At one point Bulgarian organizers decided that they had enough and that they will withdraw their bid, because it will be impossible to organise the match on such a short notice. But Chernenko was still claiming that everything was set with Lvov organizers and that the money guarantee will come any moment now. FIDE president, Kirsan Ilyumzhinov decided to put an end to this and decided to trust Chernenko's words. He gave his personal gurantees that he will give his own money in case Chernenko doesn't come up with the money from Lvov. So it was quiet for a couple of months.

Then came October 2008 and Anand defended his title against Kramnik in a match. But there was still no word about the Challenger match. By now it was obvious that there are no organizers and no money from Lvov, but Kamsky's manager was still playing the game. Despite his personal guarantees, Ilyumzhinov decided to give the match back to Bulgarians, rather than to financise it by himself. At the FIDE Congress during the Chess Olympiad (November 2008) Kamsky was finally put in front of decision to either play the Challenger match in Bulgaria (he was strongly against it for the whole time) or he will simply get replaced by 2007 World Cup runner-up Alexei Shirov. Kamsky had no choice but to agree. He also sacked Chernenko in the process and was represented by his friend Emil Sutovsky during the negotiations.

Challenger match

The Challenger match was played from February 17th to February 26th, 2009 in Sofia, Bulgaria. The match was 'best of 8 games' played on two consecutive days followed by a rest day. If necessarry there would be rapid and blitz tie-breaks to determine the winner.

Download gamess in PGN

Topalov won to become the next challenger. Originally designated time frames for these matches (see the schedule above) were already all messed up, and things got postponed further when FIDE granted Anand's request to further pospone the World Championship match and allowing him the "customary 12 months" for holding the title, meaning that the match can not be held earlier than November 2009. They eventually agreed for end of April 2010. There was only one serious bid for the match - Bulgaria, but unlike Kamsky, Anand had no objections playing there.