correlation with computer analysis. Due to his disability, Bjørnsen had been allowed to keep a record of his moves with a recorder coupled to an ear plug. The ear plug was later found to be incompatible with the recorder, but capable of receiving messages by Bluetooth. In April 2016 he received a two-year ban on domestic competition from the Central Board of the Norwegian Chess Federation (NSF). Bjørnsen's appeal to the federation's rules committee was turned down in September 2016. Bjørnsen returned in 2018 after serving the ban. In March that year he was caught with a Bluetooth earpiece taped to his hand during a club tournament in Horten. The federation expelled Bjørnsen in May 2018. In June 2021, the Indian billionaire Nikhil Kamath cheated against former world champion Viswanathan Anand in a live simultaneous exhibition charity event organised by Chess.com. The website banned Kamath's account for violating its fair play policy. The incident led to heavy criticism and discussion on social media after which Kamath confessed to using analysts and computers during his game and responded by apologising for "causing confusion". Rating manipulation Since the introduction of Elo ratings in the 1960s, a number of attempts have been made to manipulate the rating system, either to deliberately inflate one's rating or to disguise one's strength by deliberately losing rating points. Sandbagging Sandbagging involves deliberately losing rated games in order to lower one's rating so that one is eligible to enter the lower-rated section of a tournament with substantial prize money. This is most common in the United States, where the prize money for large open tournaments can be over $10,000, even in the lower-rated sections. Sandbagging is very difficult to detect and prove, so USCF has included minimum ratings based on previous ratings or money winnings to minimize the effect. Small pools of players A limited pool of players who rarely or never play against players from outside of that pool can cause distortions in the Elo rating system, especially if one or more of the players is significantly stronger than the others, or if the results are deliberately manipulated. Claude Bloodgood was accused of manipulating the USCF rating system in this way; at his peak in 1996 his USCF rating was in excess of 2700, the second highest in the country at the time. As a long-term prison inmate, he was necessarily restricted in the range of opponents