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Topalov held the top spot in the world chess rankings for six months, from October 2008 to March 2009. He achieved this feat after winning the Mtel Masters tournament in Sofia, Bulgaria, in October 2008. During his reign as world number one, Topalov played in several high-profile tournaments, including the Corus Chess Tournament in Wijk aan Zee, Netherlands, and the Linares International Chess Tournament in Spain.