How can you tell if someone is cheating in chess?

Cheating in chess has unfortunately become an issue, especially with the rise of computer engines that can easily beat even the top human players. There are many ways players can illegitimately get help during a game, but luckily there are also signs you can look for to detect potential cheating.

Sudden increase in rating or skill level

One of the most obvious indicators of potential cheating is if a player suddenly gains hundreds or even thousands of rating points over a short period of time. Or if their skill level seems to jump massively higher than what you would expect from their previous results and experience. Such dramatic improvements are very rare through legitimate study and practice alone. If a 1500 rated player is suddenly performing at a 2500 level, that should raise some red flags.

Unusually long thinking time before obvious moves

When a player is using a chess engine, they need time to input the position, analyze the computer’s suggested move, and then find a way to make the same move seem natural. This can lead to very long thinking times, even on simple or forced moves that would not require much calculation. If your opponent is spending 10 minutes on moves that require little thought, they may be trying to avoid playing the computer’s move too quickly.

Perfect play

While very strong chess players can certainly play near perfectly at times, no human plays flawlessly game after game. If your opponent is never miscalculating, missing tactics, or making even slight positional errors, that unnatural level of perfection should raise suspicions. Analyzing the game afterward with a computer will often reveal that the opponent matched the engine’s top moves every single time, far beyond normal human capabilities.

Strange mouse movements

When playing chess online, you can sometimes see the opponent’s mouse pointer during their turn. Cheaters who are inputting positions into an engine may have jerky, unnatural mouse movements as they jump back and forth rapidly. The mouse might also spend time hovering over squares where there are no pieces, indicating they are likely analyzing the position rather than calculating normally.

Regular patterns of play

If your opponent’s moves seem to follow a clear pattern each game regardless of the position, that is highly suspicious. For example,always spending the same amount of time on each move, or always moving instantly except on one move per game. This can indicate they arelikely just following computer suggestions rather than actually thinking themselves.

Strange opening choices or moves

While there are many viable openings and unusual moves in chess, there are some that are almost always suboptimal and would rarely if ever make sense for a human player to choose. Moves that deliberately go against all common chess principles could be a sign that the player is inputting moves randomly without trying to hide their cheating. This is especially true if they do not then even try to justify the odd moves.

Engine analysis shows high correlation

Analyzing a suspicious game with chess engines like Stockfish and LeelaChessZero can provide more concrete evidence of potential cheating. If the player’s moves have an unnaturally high correlation with the engine’s top choices, exceeding what even the world’s best players are capable of, that would confirm the suspicion beyond any reasonable doubt.

Obvious signs of outside assistance

There are times when cheating is blatant and overt rather than carefully hidden. Players might be caught with physical notes or computer screens with engine analysis, have headphones feeding them moves, or even have an accomplice near them signaling the best continuations. Clear cases like this erase any benefit of the doubt.


Detecting cheating in chess is challenging, but often possible through close observation and analysis. While chess engines have opened up new vulnerabilities to cheating, they also provide tools to conclusively demonstrate the likelihood of foul play. With so many honest chess players around the world, maintaining the integrity of the game remains important.

Some key signs like dramatic rating jumps, perfect move correlation, inexplicably slow play, and violation of general chess principles can all point to cheating if they happen regularly. But always remember that an isolated strange move or result does not equal cheating. Look for persistent evidence over a course of games before making any accusations.

Chess organizers also implement security measures like metal detectors, anti-computer rooms, and banned electronics to prevent cheating. But even online, your own vigilance can go a long way in catching cheaters through observation and statistical analysis. With more awareness and vigilance, chess can continue thriving as a noble game of skill.

Common Methods of Cheating in Chess

Unfortunately, some players are willing to break the rules and ethical standards to try to gain an advantage over their opponents. Here are some of the most common cheating methods chess players have been caught using:

Using Chess Engines

By far the most prevalent way players cheat today is by using computer chess engines like Stockfish, Rybka, Komodo or Fritz. These programs are far stronger than any human player, so getting their optimal moves provides a huge illegitimate advantage. Inputting the position into the engine, then trying to replicate the computer’s suggested move, is by far the most common online cheating method.

Hidden Electronics

Everything from small earpieces to smartphones can be used to get outside help from an engine or accomplice. Typically the electronics are concealed under clothing or inside other items. For example, GM Igors Rausis was caught with a phone inside a toilet paper holder, while several players at the Strasbourg Open in 2015 hid Bluetooth headsets under their bandanas or baseball caps.

Spectator Assistance

Having a spectator in the audience provide signals about the best moves is an age-old way of cheating. They could be using an engine themselves or even just be a strong player. Signals as subtle as how they are standing, coughing or tapping can communicate the best continuations. GM Arcangelo Ricci was banned for several years after his friend was found to be signaling moves to him during games.


Sandbagging involves intentionally lowering your rating so you get paired against weaker players who you have a very high chance of beating. Some players have been caught throwing lots of games or avoiding ELO rating tournaments to keep their rating hundreds of points below their true skill level, just to rack up major winning streaks later against overmatched opponents.

Prearranged Draws

Making deals with your opponent in advance to draw a game is considered cheating in most serious tournaments. While draws are acceptable if they happen naturally, predetermining the result denies the spirit of fair competition. Yet organized groups have been caught colluding to trade wins and draws to boost their ratings or tournament standings.

Famous Cases of Cheating in Chess

While most chess players compete ethically, these high-profile cases of grandmasters and other top players caught cheating drew major scandal and punishment:

Igor Rausis

A renowned grandmaster, Igor was the world’s oldest player in the top 100 at age 58 when he was banned in 2019 for cheating. He was caught repeatedly sliding a smartphone out of a toilet paper holder to check during games. Analysis found a very high correlation between Igor’s moves and’s computer engine.

Gaioz Nigalidze

A Georgian grandmaster, Gaioz was disqualified from the 2015 Dubai Open after his phone was found hidden behind a toilet mirror, wrapped in toilet paper. He had been using an app during the game but denied cheating despite extensive evidence.

Borislav Ivanov

The story of this young FM’s meteoric rise shocked the chess world as he beat multiple grandmasters. Many top players directly accused him of cheating. Though no physical evidence was found, his rating gains, play strength, and analysis suggested use of a computer program. He retired from chess a few years later.

Arcangelo Ricci

An Italian player banned for nearly 3 years after a friend was caught signaling him moves through coded coughs during a tournament. The friend had a chess computer hidden near him to indicate the strongest continuations when Arcangelo was thinking.

Sebastien Feller

A French grandmaster who enlisted accomplices to use computer assistance during games. He received a 5 year ban after extensive evidence showed his helpers analyzed positions to find winning moves for him during tournaments.

Methods for Catching Chess Cheaters

Tournament officials have implemented various approaches to try to detect cheating and maintain fair play. Here are some of the ways cheating gets uncovered:

Statistical Analysis

Running player games through chess engines to analyze the correlation between their moves and the computer’s suggestions can provide mathematical evidence of cheating beyond reasonable doubt.

Search & Seizure

Physical searches of players before and after games, including use of metal detectors and scanning wands, can catch hidden electronics. Some events even use RF frequency scanners to detect suspicious signals.

Video Surveillance

Reviewing footage of the games afterward can reveal suspicious behavior not noticed during play. Detailed video evidence has helped bust cheaters at high-level events.

Accomplice Watching

Having designated observers closely watch the players’ behavior and spectators for suspicious signals or activity. Several cheating plots have been foiled when the accomplice was caught in the act.


Interviewing players after surprising results to have them explain their thought process and moves in detail. Inconsistent logic or inability to articulate their decisions can raise red flags.

Statistical Filtering

Online platforms use algorithms to automatically flag suspicious rating gains, performance outliers, move statistics and other metrics that indicate likely cheating for further investigation.

Famous Cases of Anti-Cheating Technology in Chess

In addition to vigilance by officials, chess tournaments have used cutting-edge technology assist in catching cheaters. These include:

RF Jamming at the 2006 World Championship

To prevent any hidden wireless communication, organizers placed an RF scrambler under the stage at the Kramnik vs. Topalov title match. This generated a disrupted field that blocked any potential external signals to either player.

The “Chess Lie Detector” Algorithm

Developed by Ken Regan, this statistical model analyzes player moves compared to chess engines to detect outliers with greater than 99% certainty. It has become a trusted tool for discovering likely cheating in many tournaments when used alongside other evidence.

Screening Rooms at the 2020 Online Olympiad

Special isolated rooms were set up for players during games to prevent access to any outside help. Proctors monitored the live video feeds and the players themselves to ensure fair play.

Smartphone Bans at Major Events

Following several cheating incidents involving phones, most top tournaments now ban players from having any electronic devices inside the playing venue. Phones must be left outside to remove the temptation.

Brain Scans for Pre-Game Intellectual Property

An idea that has been proposed but not actually implemented is brain scanning of top players before tournaments to record their intellectual property. Any drastic change later could reveal potential cheating by having an accomplice stand in for games.

Steps Chess Sites & Communities Take Against Cheating

Online chess servers and local chess clubs play an important role in maintaining integrity and fairness in the game. Here are some of the anti-cheating policies they enforce:

Account Bans

Cheating accounts get permanently banned to prevent repeat offenses. Membership in the community is considered a privilege that you lose if caught violating the rules.

Rating Refunds

Any rating points gained by cheating get revoked. This penalizes and deters rating manipulation by returning inflated ratings back to their true level.

Computer Move Screening

Moves get automatically screened for unusual computer correlation. Players whose moves match engines too frequently face additional scrutiny and analysis of their account.

Limiting New/Anonymous Accounts

Restrictions on brand new or anonymous accounts make it harder to evade detection by creating alternate cheating personalities.

Volunteers Reporting

Trusted members who report suspected cheating help moderators know who to focus on. But accusations still require definitive proof.

Certified Fair Play Sections

Special sections of the rating pool only permit players who have certified their account is only used by them personally, and agrees to extra screening.

Vigilant Moderation

Having an active team that reviews reports and accusations to hand out discipline against clear cheating activity while protecting fair players.

Why Chess Cheating Is Taken So Seriously

There are several good reasons why the chess community treats cheating very harshly compared to other competitive games:

Chess is Traditionally a Gentleman’s Game

Chess has a long tradition and history of being considered a noble game of skill and intellect. So cheating represents a deep betrayal of the core values and ethics chess is meant to embody.

Ratings Have Real Prestige

A higher chess rating brings significant status and validation. When people artificially inflate their ratings through cheating, they take those achievements away from honest players who earned them.

Titles Depend on Rating Milestones

Cheating to gain ratings can allow players to earn titles like Candidate Master, Master, or Grandmaster that they don’t deserve. This damages the legitimacy of the title system.

Cheating Can Lead to Major Prizes

Chess cheating scandals have involved very large sums of prize money at prestigious events like national and world championships. The stakes are high for people willing to cheat.

Chess is Beloved for its Purity

For centuries chess has been loved for being a pure game of skill and intellect. Allowing rampant cheating threatens to damage the beautiful, noble essence of what chess represents.

Preventing Chess Cheating in Your Games

While major tournament cheating makes headlines, cheating can also happen in casual play. Here are some tips to promote fair games when you play:

Know Your Opponent

Play against people you or others in your community know well and trust to compete honestly. Avoid anonymous strangers if you suspect they are sandbagging or cheating.

Disable Computer Assistance Options

On apps and chess sites, disable any options that give hints or computer analysis during the game so players are relying purely on their own skill.

Confront Suspicious Behavior

If you notice your opponent behaving strangely, call them out and ask them to explain their actions. Make it clear you don’t tolerate cheating.

Have a Witness

When possible, have a neutral observer watch your game who can verify neither player is cheating. This adds accountability.

Don’t Share Plans or Ideas

Avoid discussing openings or general ideas with your opponent before the game. Sharing info could inadvertently help a cheater know what to prepare for.

Analyze afterward with a Computer

If you feel your opponent’s moves were too perfect, run the game through an engine after to see if there are statistical signs they got outside help.

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