Si Jiahui ( ; born 11 July 2002) is a Chinese professional snooker player. After training at the Wiraka Billiard Academy in Foshan, he moved to the United Kingdom aged 16 and earned a two-year tour card through the 2019 Q School for the 2019âÂÂ20 and 2020âÂÂ21 seasons. He lost his tour card after ending the 2020âÂÂ21 season outside the top 64 in the world rankings, and competed as an amateur during the 2021âÂÂ22 season, during which he defeated Shaun Murphy 6âÂÂ5 in the first round of the 2021 UK Championship. After rejoining the professional tour at the start of the 2022âÂÂ23 season, he reached his first ranking quarter-final at the 2022 European Masters.
At the 2023 World Snooker Championship, Si won three qualifying matches to reach the tournament's final stages at the Crucible Theatre for the first time. He then defeated Murphy, Robert Milkins, and Anthony McGill as he progressed to the semi-finals, becoming the first Crucible debutant to reach the last four since Andy Hicks in 1995. Although he led 14âÂÂ5 in the semi-final, he lost 15âÂÂ17 to the eventual winner Luca Brecel; this nine-frame deficit was the largest lead overturned in the history of the World Championship. He advanced from 80th to 36th in the world rankings after the tournament. Si reached the first ranking final of his career at the following season's 2024 German Masters, but lost 5âÂÂ10 to Judd Trump.
Si achieved his first maximum break in professional competition in his 6âÂÂ2 win against Judd Trump in the semi-final of the 2024 Wuhan Open. In his second ranking final, Si lost against Xiao Guodong.
Born on 11 July 2002, in the district of Zhuji, in Zhejiang, Si resided with his parents in Hangzhou. He competed in table tennis tournaments as a child, winning second place in a school tournament and competing in other tournaments in the city. He became interested in cue sports after his father opened a pool club dedicated to Chinese eight-ball. Si showed talent at the sport, and his father pressured him to excel at it. By age 10, Si was practising for 13 hours a day under the supervision of his father and beating all other players at the club.
Si entered a nine-ball tournament in Shanghai for elementary school students, where he was runner-up. At the tournament, his father met another father whose son was training at a snooker academy in Guangdong. In September 2013, aged 11, Si left school and moved to Guangdong, accompanied by his father, where he began playing snooker. At age 12, he began training at the Wiraka Billiard Academy in Foshan, where he was coached by Roger Leighton. At 14, he defeated former world number one Ding Junhui 3âÂÂ2 in a national tournament.
At age 16, Si moved to the United Kingdom. He joined VictoriaâÂÂs Snooker Academy in Sheffield, a stable of mostly Chinese players managed by former snooker journalist Victoria Shi. Other players at the Academy upon Si's arrival included Zhao Xintong, Yan Bingtao, and Fan Zhengyi.
Si received a two-year professional tour card through the 2019 Q School for the 2019âÂÂ20 and 2020âÂÂ21 seasons. However, he was relegated from the World Snooker Tour after finishing the 2020âÂÂ21 season 92nd in the snooker world rankings, below the cut-off at 64th position.
Si spent the 2021âÂÂ22 season competing as an amateur, but earned top-up places in ranking tournaments through his high placement in the 2021 Q School Order of Merit. At the 2021 UK Championship, he defeated former world champion Shaun Murphy 6âÂÂ5 in the first round. In a BBC radio interview after the match, Murphy objected to amateur players featuring in professional events, saying that he had "lost to someone who shouldnâÂÂt even be in the building". The World Snooker Tour issued a statement disagreeing with these remarks, and Murphy subsequently apologised for "taking the shine off" Si's win.
Towards the end of the season, Si won the 2022 World Snooker Federation Open amateur event, defeating Lee Stephens 5âÂÂ0 in the final. This win earned him a two-year professional tour card for the 2022âÂÂ23 and 2023âÂÂ24 seasons. At the 2022 European Masters, he defeated Anthony McGill and Daniel Wells to reach his first quarter-final at a ranking event, which he lost 2âÂÂ5 to Kyren Wilson.
Ranked 80th in the world rankings, he qualified for the main stage of the 2023 World Snooker Championship after defeating Florian NüÃÂle 10âÂÂ7, Tom Ford 10âÂÂ5, and Jordan Brown 10âÂÂ7 in the qualifying rounds. In the first round at the Crucible Theatre, Si defeated Murphy 10âÂÂ9. On this occasion, Murphy commented on how well Si had played, saying he had been "fabulous". Si defeated Robert Milkins 13âÂÂ7 in the second round and McGill 13âÂÂ12 in the quarter-finals, becoming the first Crucible debutant to reach the World Championship semi-finals since Andy Hicks in 1995 and the youngest player to do so since Ronnie O'Sullivan in 1996. Si lost 15âÂÂ17 to Luca Brecel in the semi-finals after Brecel, from 5âÂÂ14 down, won 12 of the last 13 frames. Si advanced from 80th to 36th in the world rankings as a result of his performance at the tournament.
Si reached the first ranking final of his career at the following season's 2024 German Masters, but lost 5âÂÂ10 to Judd Trump. At the 2024 World Championship, he defeated Mark Williams 109 in the first round and then lost 913 to Jak Jones in the last 16. The 2025 Masters marked his first appearance at the tournament, but Si lost in the first round to Mark Allen 26. At the 2025 World Championship, Si advanced to the quarter-finals where he was defeated by O'Sullivan 913.
Si lives in Sheffield during the snooker season. He did not see his family or his friends during the COVID-19 pandemic; after the 2023 Welsh Open, he visited China for the first time in three years. During the 2020âÂÂ21 season, he dyed his hair blue.