Sergey Alexandrovich Karjakin is a Russian chess grandmaster. Formerly a Ukrainian citizen, Karjakin switched his nationality to Russian in 2009. He is a former chess prodigy and holds the record for the world's youngest grandmaster, achieving this title at the age of 12 years and 7 months.
Karjakin has won multiple chess tournaments throughout his career. He won the 2012 World Rapid Chess Championship, the Norway Chess Tournament twice (in 2013 and 2014), the 2015 Chess World Cup, and he was also the runner-up in the 2016 World Chess Championship.
Karjakin represented Ukraine at the 2004 Chess Olympiad, where he clinched gold in board one. After moving to Russia, he won silver and bronze in the 2010 and 2012 Chess Olympiads, respectively. In 2016, he played one of the longest games in World Chess Championship history (in terms of moves), lasting 149 moves against Magnus Carlsen.
Karjakin is known for his strong defensive playing style and for his deep opening preparation. He is also a regular player in top-level team events and has been a major contributor to Russian and Ukrainian team successes in these competitions.