Jose Capablanca - History Part 4 (World Champion)
In 1919, Capablanca overwhelmed the strong Serbian Kostic in a match at Havana with five straight wins, whereupon Kostic resigned the match. Capablanca later wrote in 1927 that he had played the best chess of his life in this match. Capablanca also won the Hastings 1919 Victory tournament with a dominant 10½/11, a point ahead of Kostic.
In 1920, Lasker saw that Capablanca was becoming too strong, and resigned the title to him, saying, "You have earned the title not by the formality of a challenge, but by your brilliant mastery." Capablanca wanted to win it in a match, but Lasker insisted that he was now the challenger. They played a match in Havana in 1921, and Capablanca defeated Lasker +4 -0 =10. This feat of winning the world title without losing a game to the incumbent went unequaled for almost eight decades, until Vladimir Kramnik's win over Garry Kasparov +2 -0 =13 in 2000.
The new world champion, Capablanca dominated the field at London, 1922, with 13/15, ahead of Alexander Alekhine (11½), Milan Vidmar (11), and Akiba Rubinstein (10½). There was an increasing number of strong chess players and it was felt that the world champion should not be able to evade challenges to his title, as had been done in the past. At this tournament, some of the leading players of the time, including Alexander Alekhine, Efim Bogoljubov, Geza Maroczy, Richard Reti, Akiba Rubinstein, Savielly Tartakower and Milan Vidmar, met to discuss rules for the conduct of future world championships. Amongst other things, one of the conditions proposed by Capablanca was that the challenger would have to raise at least ten thousand dollars for the prize money. These were the so-called 'London Rules'. That same year, Capablanca gave a simultaneous exhibition against 103 opponents, the largest in history up to that time, and scored 102 wins and 1 draw, losing none.
In the following years, Rubinstein and Nimzowitsch challenged Capablanca, but were unable to raise the stipulated funds. Alekhine's subsequent challenge, in 1927, was backed by a group of Argentinian businessmen and the president of Argentina who guaranteed the funds.
Capablanca was second, with 14½ points, behind Lasker's 16, at the elite New York 1924 tournament, one of the greatest ever staged, and again ahead of third-placed Alekhine. In this tournament, his loss to Reti was his first in eight years. His performance was still a superb 2792. At Moscow 1925, Capablanca scored 13½ for third place, behind Efim Bogoljubov (15½) and Emanuel Lasker (14); this was a 2760 performance. Capablanca won at Lake Hopatcong 1926 with 6/8, ahead of Abraham Kupchik (5) and Geza Maroczy (4½). 
As World Champion, Capablanca also underwent major changes in his personal life. In December 1921, he married Gloria Simoni Betancourt. They had a son, José Raúl Jr., in 1923 and a daughter, Gloria, in 1925, but the marriage ended in divorce.