Answers.Body: <p>How could you cheat? This is what the <a href="https://lichess.org/terms-of-service" rel="noreferrer">Lichess terms of service</a> say about it:</p>
  
  <blockquote>
    <p><strong>Cheating</strong>. We define this as using any external assistance to
    strengthen your knowledge and, or, calculation ability to gain an
    unfair advantage over your opponent. Some examples would include
    computer engine assistance, opening books (except for correspondence
    games), endgame tablebases, and asking another player for help,
    although these aren’t the only things we would consider cheating.</p>
  </blockquote>
  
  <p>The most common form of cheating is using an engine. I don't know the details of what Lichess does, but cheating detection can consist of comparing a player's moves to those proposed by various engines, and based on statistical analysis one can come up with criteria for when the player's moves were "suspiciously similar" to an engine's.</p>
  
  <p>Lichess also allows people to register bot accounts, but those must be clearly labelled as bots. So I suppose that another form of cheating could be to create a bot account and pretend that it is a human.</p>
  
  <p>I also found <a href="https://web.archive.org/web/20160610172814/http://en.lichess.org/qa/258/all-about-cheating-questions-and-answers" rel="noreferrer">this old FAQ</a>:</p>
  
  <blockquote>
    <ol start="4">
    <li>How are cheaters identified?</li>
    </ol>
    
    <p>A:</p>
    
    <ul>
    <li>Using the suspicious games themselves. The degree to which computer players differ in playing style and strength, to most human opponents
    that rely on them, is in most cases enough to reverse-engineer
    information from the game beyond what moves were made.</li>
    <li>Using the player's other games. A player's profile shows all their games, including games where it is apparent that there was no
    cheating. Games where a player cheated and games where a player did
    not cheat have very different results when reviewing them using a
    chess engine (or Lichess' computer analysis feature).</li>
    <li>Using the player's history. On every player's profile are public graphs of rating and average history, game database exports upon
    request, and win to loss ratio.</li>
    <li>Time statistics. Anyone can see the public time consummation information for games, i.e., the time-per-moves.</li>
    <li>A statistical analysis of the suspected user's playing behaviour. This statistical analysis is only visible to the lichess team.</li>
    <li>Copying and pasting the suspicious game(s) into an engine and seeing how similar the moves are.</li>
    </ul>
  </blockquote>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-02-19T16:32:27.350Z
Answers.Text: Lichess monitors your mouse movements and can detect switching back and forth between browser and engine. Check the javascript. Note that this is by no means foolproof, but it catches a lot of people anyway.
Answers.UserDisplayName: Joshua
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-11-25T16:43:18.580Z
Answers.LastActivityDate: 2019-11-25T16:48:29.770Z
Answers.LastEditDate: 2019-11-25T16:48:29.770Z
Answers.UserDisplayName: itub
Answers.Body: <p>If you go on chess.com you will see that you can analyze games in a lot of detail. This analysis can compare to state of the art chess engines and determine whether your moves were "human-like" in their accuracy (for each piece) or if you simply made "engine-like" moves. For example, if each one of your moves was classified as the best possible move in that position - that would raise a flag especially if your rating is nowhere near the engine that would struggle to make those moves.</p>
  
  <p>On that note, if you play on lichess (slow games), your opponent could theoretically use the board editor and analysis tools to make your moves and see what the computer would do in response. Then they would simply play those moves against you.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-11-26T21:31:41.250Z
Answers.LastActivityDate: 2019-11-26T21:31:41.250Z
Answers.UserDisplayName: lbragile
Body: <p>I was playing a game on Lichess the other day and all of a sudden the system ended the game, awarded me the victory, and said &quot;Cheating by White detected&quot;.</p>
  <p>How in the world could you cheat on Lichess? Does anyone know what this means? My rating is 1250 – who would bother to cheat against me?</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-11-26T07:19:20.377Z
Comments.Text: That message usually only occurs if someone actually has the audacity to use lichess' own analysis board to get the best moves for your game WHILE playing you. As for the motivation: People really like imaginary internet-points (like your lichess rating...) - some will do unethical things to raise them, e.g. cheat in online chess.
Comments.UserDisplayName: Benjamin Raabe
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-11-26T17:41:52.183Z
Comments.Text: I've also (unknowingly and unintentionally) been flagged in a game as a cheater for having the Lichess analysis open at the same time as playing (and analyzing my moves as I played them).
Comments.UserDisplayName: PenumbraBrah
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-11-26T21:36:31.977Z
Comments.Text: @TheHonestAtheist, analyzing your game while you are playing is technically cheating as you are getting information about your position which gives you unfair advantage in terms of extra outside information.
Comments.UserDisplayName: lbragile
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2024-04-29T14:34:30.257Z
Comments.Text: I had this happen when I was using Lichess's opening book during a correspondence game, which I think is allowed.
Comments.UserDisplayName: qwr
Tags: <online-chess><cheating><lichess>
Title: How could one cheat on Lichess?
ThreadText: # How could one cheat on Lichess?
  
  (Asked by: username_0 on 2019-11-25)
  
  I was playing a game on Lichess the other day and all of a sudden the system ended the game, awarded me the victory, and said "Cheating by White detected".
  
  How in the world could you cheat on Lichess? Does anyone know what this means? My rating is 1250 – who would bother to cheat against me?
  
  **Tags:** online-chess, cheating, lichess
  
  > **Comments:**
  > **username_1**: That message usually only occurs if someone actually has the audacity to use lichess' own analysis board to get the best moves for your game WHILE playing you. As for the motivation: People really like imaginary internet-points (like your lichess rating...) - some will do unethical things to raise them, e.g. cheat in online chess.  
  > **username_2**: I've also (unknowingly and unintentionally) been flagged in a game as a cheater for having the Lichess analysis open at the same time as playing (and analyzing my moves as I played them).  
  > **username_3**: @TheHonestAtheist, analyzing your game while you are playing is technically cheating as you are getting information about your position which gives you unfair advantage in terms of extra outside information.  
  > **username_4**: I had this happen when I was using Lichess's opening book during a correspondence game, which I think is allowed.  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_5 on 2019-11-25. Score: 32
  
  How could you cheat? This is what the [Lichess terms of service](https://lichess.org/terms-of-service) say about it:
  
  > **Cheating**. We define this as using any external assistance to
  > strengthen your knowledge and, or, calculation ability to gain an
  > unfair advantage over your opponent. Some examples would include
  > computer engine assistance, opening books (except for correspondence
  > games), endgame tablebases, and asking another player for help,
  > although these aren’t the only things we would consider cheating.
  
  The most common form of cheating is using an engine. I don't know the details of what Lichess does, but cheating detection can consist of comparing a player's moves to those proposed by various engines, and based on statistical analysis one can come up with criteria for when the player's moves were "suspiciously similar" to an engine's.
  
  Lichess also allows people to register bot accounts, but those must be clearly labelled as bots. So I suppose that another form of cheating could be to create a bot account and pretend that it is a human.
  
  I also found [this old FAQ](https://web.archive.org/web/20160610172814/http://en.lichess.org/qa/258/all-about-cheating-questions-and-answers):
  
  > 4. How are cheaters identified?
  >
  > A:
  >
  > * Using the suspicious games themselves. The degree to which computer players differ in playing style and strength, to most human opponents
  >   that rely on them, is in most cases enough to reverse-engineer
  >   information from the game beyond what moves were made.
  > * Using the player's other games. A player's profile shows all their games, including games where it is apparent that there was no
  >   cheating. Games where a player cheated and games where a player did
  >   not cheat have very different results when reviewing them using a
  >   chess engine (or Lichess' computer analysis feature).
  > * Using the player's history. On every player's profile are public graphs of rating and average history, game database exports upon
  >   request, and win to loss ratio.
  > * Time statistics. Anyone can see the public time consummation information for games, i.e., the time-per-moves.
  > * A statistical analysis of the suspected user's playing behaviour. This statistical analysis is only visible to the lichess team.
  > * Copying and pasting the suspicious game(s) into an engine and seeing how similar the moves are.
  
  > **Comments:**
  > **username_6**: Lichess monitors your mouse movements and can detect switching back and forth between browser and engine. Check the javascript. Note that this is by no means foolproof, but it catches a lot of people anyway.  
  
  ---
  
  ### Answer by username_3 on 2019-11-26. Score: 3
  
  If you go on chess.com you will see that you can analyze games in a lot of detail. This analysis can compare to state of the art chess engines and determine whether your moves were "human-like" in their accuracy (for each piece) or if you simply made "engine-like" moves. For example, if each one of your moves was classified as the best possible move in that position - that would raise a flag especially if your rating is nowhere near the engine that would struggle to make those moves.
  
  On that note, if you play on lichess (slow games), your opponent could theoretically use the board editor and analysis tools to make your moves and see what the computer would do in response. Then they would simply play those moves against you.
  
  
  ---
  
  