Iyama Yuta (井山 裕太, Iyama Yūta, b. 24 May 1989) is a Japanese, professional 9-dan of the Nihon Kiin Kansai branch. He began as a renowned child prodigy and has become one of the most dominant players in contemporary Japanese go. In 2013 and again in 2015 he held six of the seven major Japanese titles. In 2016 he became the first person to hold all seven titles simultaneously, and repeated the feat in 2017.
Iyama was born on May 24th, 1989. At the age of five he learned Go after watching his dad play on the computer. In about a year he became a Japanese 3-dan and soon after become a pupil of Ishii Kunio 9-dan. Together they would play over 1,000 online games. During this period he began to be known as a child prodigy due to his quick improvement and number of wins in youth tournaments.
In October 1998, Iyama became an insei. He challenged for a professional spot in 2001, but lost to Kohei Kawada. The following year (2002) he tried again and this time earned his professional status -- becoming the fifth youngest professional. At the age of 16, he established the current records for youngest professional to hold a Japanese professional open title (the Agon Cup), and the youngest to reach the rank of 7-dan. In 2008, he was promoted to 8-dan for becoming the challenger for the 33rd Meijin title; and in 2009 to 9-dan for winning the 34th Meijin title. At this point he became the youngest Japanese professional to hold one of seven big Japanese titles and the youngest Japanese 9-dan.
In March 2013, Iyama won the 37th Kisei, making him the youngest person to have held all seven titles, the youngest to simultaneously hold six of the seven major titles at once, the youngest Kisei winner at 23-years and 9-months (the previous record was Cho Chikun at 26-year and 5-months), and third person have held all seven titles (after Cho Chikun and Cho U respectively). Recapturing the Meijin title in October 2013 meant that Iyama held every one of the seven major titles during the same year, though not simultaneously.
In April 2016 Iyama won the 54th Judan, finally becoming the first player ever to hold all seven major titles simultaneously.
In September 2016 Iyama also won the Honinbo title for the fifth time in a row, thus qualifying for becoming an "eternal Honinbo" and choosing a name for himself. On September 9, he unveiled his new name: 文裕 (Monyu). The first character is taken from the name of his grandfather, who taught him how to play Go. The second character is taken from his own given name. 
In November 2016, he achieved six wins in the Tengen title, beating Rin Kaiho's record which had stood since 1993.
An Younggil has said several things of Iyama:
"Iyama is also very good at local fighting. His play isn't typical Japanese style. He plays rather severely and sharply."
"...he doesn't generally start fighting, but rather waits for the right time to fight." & "Iyama is also a genuine fighter."
"Iyamas style of play is thick and solid."
"Iyama prefers a fighting game, as he's confident at fighting and still quite young. In general, younger players tend to be keener on fighting."
"Iyama's not worried about a fighting game, but it looks like he still prefers this sort of territorial game compared to other top players from China and Korea."
"He seems to like to play solidly, and doesn't mind a large moyo game."
- 2002: 1d
- 2002: 2d 
- 2003: 3d
- 2004: 4d - Promoted from 3- to 4-dan for leading the prize-money list among 3d professionals.
- 2005: 7d - Promoted from 4- to 7-dan for winning the 12th Agon Cup.
- 2008: 8d - Promoted from 7- to 8-dan for challenging for the 33rd Meijin.
- 2009: 9d - Promoted from 8- to 9-dan for defeating Cho U to win the 34th Meijin.
- 1998: 19th All Japan Children's Tournament, Junior school section
- 2005: 12th Agon Cup
- 2005: 2nd Nakano Cup
- 2006: 3rd Nakano Cup
- 2007: 4th Nakano Cup
- 2007: 32nd Shinjin-O
- 2008: 1st Daiwa Grand Champion Cup
- 2009: 2nd Daiwa Grand Champion Cup
- 2009: 2nd Yugen Cup
- 2009: 18th Ryusei
- 2009: 34th Meijin
- 2010: 35th Meijin
- 2010: 6th Daiwa Shoken Cup
- 2011: 49th Judan
- 2011: 1st Bosai Cup
- 2011: 20th Ryusei
- 2011: 18th Agon Cup
- 2011: 37th Tengen
- 2012: 7th Daiwa Shoken Cup
- 2012: 50th Judan
- 2012: 67th Honinbo
- 2012: 37th Gosei
- 2012: 21st Ryusei
- 2012: 60th Oza
- 2012: 38th Tengen
- 2013: 37th Kisei
- 2013: 25th Asian TV Cup
- 2013: 68th Honinbo
- 2013: 38th Gosei
- 2013: 38th Meijin
- 2013: 39th Tengen
- 2013: 61st Oza
- 2014: 38th Kisei
- 2014: 69th Honinbo
- 2014: 39th Gosei
- 2014: 39th Meijin
- 2015: 39th Kisei
- 2015: 70th Honinbo
- 2015: 40th Gosei
- 2015: 40th Meijin
- 2015: 41st Tengen
- 2015: 63rd Oza
- 2016: 40th Kisei
- 2016: 54th Judan
- 2016: 71st Honinbo
- 2016: 41st Gosei
- 2016: 64th Oza
- 2016: 42nd Tengen
- 2017: 41st Kisei
- 2017: 55th Judan
- 2017: 42nd Gosei
- 2017: 42nd Meijin
- 2017: 65th Oza
- 2017: 43rd Tengen
- 2017: 72nd Honinbo
- 2018: 42nd Kisei
- 2018: 56th Judan
- 2005: Shinjin O, runner-up
- 2008: 33rd Meijin, runner-up
- 2011: 24th Fujitsu Cup, 3rd place
- 2018: 22nd LG Cup, runner-up
- 2002: 21-4
- 2003: 32-13
- 2004: 25-7
- 2005: 40-13
- 2006: 3414
- 2007: 4411
- 2008: 4821
- 2009: 4314
- 2010: 3420
- 2011: 4819
- 2012: 51-12
- 2013: 43-18
- 2014: 31-18
- 2015: 42-11
Record as of 2014-12-31: 494 wins, 184 losses.
 Daily Yomiuri article (English): http://www.yomiuri.co.jp/dy/national/T130315004814.htm
 For example, winner of the 1997 & '98 National Elementary School Championship.
 "Iyama wins Agon Kiriyama Cup": http://www.nihonkiin.or.jp/english/topics/05/topics2005_10.htm.
 "Iyama to challenge for Meijin title": http://www.nihonkiin.or.jp/english/topics/08/topics2008_07.htm.
 "Iyama Yuta becomes youngest Meijin, sets new records" & "Promotions": http://www.nihonkiin.or.jp/english/topics/09/topics2009_10.htm.
 He succeeded the Nihon Kiin's previous record for fastest promotion to 9-dan by 7-years, 6-months.
 "Cho U defends Meijin title in 7th game": http://www.nihonkiin.or.jp/topics2008/topics11.html.
 "Promotions": http://www.nihonkiin.or.jp/english/topics/02/topics2002_09.htm.
 "2004 promotions": http://www.nihonkiin.or.jp/english/topics/05/topics2005_03.htm.
 Go Commentary: Gu Li vs Iyama Yuta 1st Bosai Cup: http://gogameguru.com/commentary-gu-li-iyama-yuta-1st-bosai-cup/
 Go Commentary: Gu Li vs Iyama Yuta 24th Fujitsu Cup: http://gogameguru.com/commentary-gu-li-iyama-yuta-24th-fujitsu-cup/
 Go Commentary: Yamashita Keigo vs Iyama Yuta 67th Honinbo Game 5: http://gogameguru.com/go-commentary-yamashita-keigo-iyama-yuta-67th-honinbo-game-5/
 Go Commentary: Iyama Yuta vs. Hane Naoki, 37th Gosei, Game 3: http://gogameguru.com/go-commentary-iyama-yuta-hane-naoki-37th-gosei-game-3/
 Go Commentary: Lee Younggu vs Iyama Yuta 18th LG Cup: http://gogameguru.com/go-commentary-lee-younggu-vs-iyama-yuta-18th-lg-cup/
 Go Commentary: Park Junghwan vs Iyama Yuta 25th Asian TV Cup: http://gogameguru.com/go-commentary-park-junghwan-vs-iyama-yuta-25th-asian-tv-cup/
 The Power Report, September 25th 2016: http://www.usgo.org/news/2016/09/the-power-report-1-honinbo-monyu-takao-sweeps-to-3-0-lead-in-meijin-challenge-yuki-wins-kisei-b-league-play-off/
- Nihon Kiin profile: http://www.nihonkiin.or.jp/player/htm/ki000385.htm.
- A post by John Fairbairn about his early life and career: http://lifein19x19.com/forum/viewtopic.php?f=13&t=3873.
- Anonymous: Not to take anything away from Iyama's performance but it was harder to reach 9-dan under the old oteai ranking system. Promotions to 9-dan by recommendation did occur, e.g. Go Seigen in 1950 after his successes in 10 game matches and Ishida Yoshio in 1974 after becoming Meijin Honinbo, but such promotions were very rare.