Ke Jie

Ke Jie (simplified Chinese: 柯洁; traditional Chinese: 柯潔; pinyin: Kē Jié; born 2 August 1997) is a Chinese professional go player of 9 dan rank. He is currently ranked number one in the world under Rémi Coulom's unofficial ranking system.

Ke Jie started to learn how to play go in 2003 when he was 5 years old and won his first national championship in 2007. He became a professional go player in 2008 when he was 10 years old and was promoted to 9 dan rank in 2015. In January 2015, Ke won his first world title when he won the 2nd Bailing Cup, defeating Qiu Jun in the finals. In December 2015, he defeated Shi Yue in the 20th Samsung Cup finals to win another world title.

In January 2016, Ke won the 2nd Mlily Cup, defeating world renowned go player Lee Sedol in the fifth round. According to 9 dan South Korean professionals commenting on the final game, the result hinged on a half-point ko and the peculiarities of Chinese scoring rules; however, others have pointed out that this argument is misleading as differences in komi between the Chinese and Japanese scoring systems would have made up the extra point, leading to the same result. On 11 February 2016, he defeated Lee once more in the finals of the 2016 HeSui Cup.On 5 March 2016, Ke defeated Lee yet again in the finals of the 2016 Nongshim Cup to win the tournament for the Chinese squad, making it China's third consecutive win of the tournament.

On 4 June 2016, at a news conference during the 37th World Amateur Go Championship, Yang Jun'an, the party chief of the Zhongguo Qiyuan and executive of the International Go Federation, revealed that AlphaGo would possibly have a match against Ke in the future. However, Demis Hassabis responded that Google DeepMind had not yet decided what to do next with AlphaGo.

In August 2016, at the 3rd Bailing Cup, Ke defeated Xu Jiayang to advance to the best of three semifinal match where he faced Won Seong-jin. In the first game, Won defeated Ke with a comeback victory after Ke had made very crucial mistakes when analyzing territory turnover; however, he was able to bounce back from the defeat by playing a very close endgame in which he maintained a territorial lead. In the deciding third game, he continued to make advantageous moves during the middle-game phase in which he again had a comfortable territorial lead but also forcing a successful ko fight at the top of Won's territory, forcing the latter to resign because of a lack of ko resources. Ke then faced Chen Yaoye in the final which was the third straight Bailing Cup finals to have been contested between Chinese players. The first two games of the best of five matchup was both won by Chen. In the first game, Chen displayed enormous tenacity in chasing and eventually leading in territory with very little ko's for Ke to win in the endgame. The second game was a mirror of the first, but during the middle game, Ke deviated and began to chase and attack Chen's dragon, forcing Chen to maneuver around the middle of Ke's territory; however, during the chase, Ke's 105th move was a blunder that allowed Chen to retaliate and take the initiative, causing the match to eventually end on move 178.

From 31 October 2016 to 2 November 2016, during the 21st Samsung Cup, Ke played against rival Lee Sedol once more during the semifinals.

In the first game of the best of three series, Ke was reported to have won a very complete game in which Lee had very few chances due to the endgame being non-existing for him; however, with no breaks between games, Ke slipped up with his advantage with the white stones and Lee produced one of his many trademark comeback victories. The game began very evenly until Ke acquired a huge lead in territory and a positional advantage, but a few slip-ups when fighting Lee's dragon in the centre of the board caused Ke to lose his bearings in terms of maintaining his advantage. A few more accurate moves by Lee turned the tides, and with the safety of his dragon and gaining the territorial advantage, he closed out the second game to produce a stunning comeback win. With both games won by resignation with black, the third game had both players do coin-toss for the picking of the stones. Ke had the white stones in the deciding game and acquired all four corners and a marked territorial lead straight from the beginning. The remainder of the game displayed his ability to invade and scrape away Lee's territorial potential. As Lee began to find it difficult to gain any territory advantage, he pressed on the weaknesses of white's territory hoping to gain some advantage, but Ke made no mistakes and did not allow for the comeback to occur. With Lee's resignation in the deciding game, Ke reached the 21th Samsung Cup finals for the second year straight. From 6 December 2016 to 8 December 2016, Ke played the finals against compatriot Tuo Jiaxi. After losing the first game with black, Ke won the second game with white to even the series and then won the decider with black to successfully defend his Samsung Cup title.

As of 16 December 2016

As of 1 January 2017

• Total: 238 wins, 97 losses (71.0% winning percentage)

As of 1 January 2017

Players who have won international go titles in bold.