Ms. Hou defeated another Chinese player, Ruan Lufei, in the final of the Women’s World Chess Championship, which was held in Antakya, Turkey.

In a telephone interview after the competition, Ms. Hou was excited, but also critical of her play against Ms. Ruan, a lower-ranked opponent. The final was decided in playoff games after the four-game regulation match ended in a tie. “I think before the final, my play was very good,” Ms. Hou said. “The final match, I am not very satisfied with that.”

Maia Chiburdanidze of the Republic of Georgia had previously held the record for youngest champion. She won the title in 1978, when she was 17, and held it until 1991, when she was defeated by Xie Jun of China.

The record among men is held by Garry Kasparov, who became world champion in 1985, when he was 22.

Ms. Hou had an earlier shot at the women’s world title in 2008, when she was 14, but lost in the championship match to Alexandra Kosteniuk of Russia. She said that Ms. Kosteniuk had simply been too good at the time. “She did not give me many chances,” Ms. Hou said. Ms. Kosteniuk was defeated early in this year’s tournament.

Ms. Hou is a solid player who takes few risks in her games, but also rarely makes critical mistakes. She has been among the best female players since 2006, when she suddenly rose to No. 8 in the world. She is now No. 3, but could surpass Humpy Koneru of India, the current No. 2, if her world championship victory is taken into account in the next rankings, which are due to be released Jan. 1. Ms. Hou defeated Ms. Koneru in the semifinals of the championship tournament.

Currently, the top-ranked woman is Judit Polgar of Hungary, who is thought to be the best female player in history. Ms. Polgar does not compete in women’s tournaments and did not play in the championship in Turkey. She once was ranked No. 8 in the world among all players, men and women combined.

No one really knows why the best female players are typically not as good at chess as the best men. One theory, common among some top male players, is that men are usually more aggressive by nature than women, and are therefore better suited to a game that simulates warfare. Another, cited in at least one university study, is that the talent pool among women has not been big enough to produce many great players.

Ms. Hou said she had no idea why the gender disparity existed in chess, but whatever the reason, she said she found men more difficult to play against. She is looking forward to competing against men again, she said, most immediately at a tournament in January in Gibraltar.

Ms. Hou is the fourth women’s world champion from China, following Ms. Xie, who was champion from 1991 to 1996 and again from 1999 to 2001; Zhu Chen, 2001 to 2004; and Xu Yuhua, 2006 to 2008.

Ms. Hou said that she received training and financial support from the Chinese government. She studies chess four to five hours a day, and also attends high school. She said that she sometimes fell behind in her work, but her teachers understood and tried to help her out.