|Full name||Simen Agdestein|
|Born||15 May 1967|
|FIDE rating||2552 (September 2021)|
|Peak rating||2637 (July 2014)|
Agdestein won seven Norwegian chess championships, including the 2005 title. He is also the former coach of Magnus Carlsen, and brother of Carlsen's manager, Espen Agdestein. He has authored and co-authored several books on chess, including a biography of Carlsen.
Agdestein became Norwegian national champion at the age of 15, an International Master at 16 and a grandmaster at 18.
On a local level, his regular dominance of the Nordic and Norwegian Chess Championships during the 1980s amply demonstrated that there were few players who could resist his enterprising and inventive style. In international competition, he finished second at the 1986 World Junior Championship behind Walter Arencibia but ahead of Evgeny Bareev, Viswanathan Anand and Jeroen Piket. A little later, his Elo rating rose to over 2600.
In the late 1980s, Agdestein combined top-flight chess with a full-time football career, representing his country at both. In the early 1990s, a knee injury cut short his football activities. In 1999, Agdestein returned to winning ways, topping the Cappelle la Grande tournament that year and the Isle of Man tournament in 2003. Agdestein scored two tournament victories in 2013, when he won the Open Sant Martí in Barcelona with 8½ points out of 9 possible, with a rating performance of 2901, and the Oslo Chess International-Håvard Vederhus' Memorial with 7 points out of 9.
He was born in Oslo as a son of civil engineer Reidar Frank Agdestein (1927–2002) and secretary Unni Jørgensen (1934–). He is a maternal grandson of runner and botanist Reidar Jørgensen. In 1995, he was awarded a master's degree from the Department of Political Science at the University of Oslo. In October 1996 he married Marianne Aasen, a later Member of Parliament. The couple had three children, but separated in 2008.
- Sjakkleksjoner med Simen Agdestein (1987)
- GATT, u-landene og miljøet : rapport fra en konferanse i Oslo 20. og 21. oktober 1994 (1994)
- Regionalt samarbeid versus apartheid : SADCC-landenes bestrebelser på å redusere transportavhengigheten til Sør-Afrika på 1980-tallet (1995) (Master thesis, University of Oslo)
- Simens sjakkbok (1997)
- Et hefte om internasjonalisering (1998)
- Den unge sjakkspiller (2001)
- Sjakk: Fra første trekk til sjakkmatt (2002)
- Wonderboy : how Magnus Carlsen became the youngest chess grandmaster in the world : the story and the games (2004)
- Sjakk (2007)
Books about Agdestein
- Arne Danielsen, Bjarte Leer-Salvesen, Bjarke Sahl, Atle Grønn. Simen Agdestein (2008)
- "Simen Agdestein som Lynspiller". Retrieved 4 December 2016.
- Norway – International Players – Landslaget
- Pein, Malcolm (8 October 2003). "Agdestein nets a winner". Daily Telegraph. Retrieved 6 June 2010.
- Valaker, Ole (21 July 2013). "Simen (46) vant storturnering i Spania" (in Norwegian). Nettavisen. Retrieved 21 July 2013.
- Valaker, Ole (6 October 2013). "- Han spiller som han var 23 år!" (in Norwegian). Nettavisen. Retrieved 6 October 2013., Crosstable of Oslo Chess International (TournamentService)
- Bartelski, Wojciech. "OlimpBase :: Men's Chess Olympiads :: Simen Agdestein". Retrieved 4 December 2016.
- Brekke, Øystein. "Simen Agdestein". In Helle, Knut (ed.). Norsk biografisk leksikon (in Norwegian). Oslo: Kunnskapsforlaget. Retrieved 3 February 2012.
- Bøckman, Knut (19 September 1989). "Navn i nyhetene: Simen Agdestein". Aftenposten (in Norwegian). p. 6.
- UiO:DUO Research Archive. https://www.duo.uio.no/handle/10852/14709
- Ekker, Bjørn (12 September 2008). "Her er "Skal vi danse"-bruddene". Se og Hør (in Norwegian). Retrieved 3 February 2012.
- "BIBSYS – Vi gjør kunnskap tilgjengelig". Retrieved 4 December 2016.