Such behaviour is regarded as cheating (see cheating in chess).

Cheating in chess - Methods that have been used to gain an unfair advantage by breaking the rules.

Over the years there have been many high profile and intriguing case of cheating in chess, using differing levels of sophistication.

Accusations of cheating in chess matches are not unprecedented, and they are sometimes a little outlandish.

Cheating in chess refers to a deliberate violation of the rules of chess or other unethical behaviour that is intended to give an unfair advantage to a player or team.

To the Editor: The April 8 Chess column discusses the new blight of cheating in chess tournaments ("As Technology Leaps Ahead, Concerns About Cheating Grow").