1. What is cheating? What is boosting? What is sandbagging?
A: In the context of the rules on Lichess, the general definition of "cheating" is when players use means other than their own chess intellect to win rated games or otherwise boost their ratings. Examples of cheating include:
- Using a computer player (or chess engine) to play the game;
- Lending access to a game to another individual for help with moves;
- Creating additional Lichess accounts to boost (boosting) or lower (sandbagging) one's rating*;
Boosting and sandbagging are both forms of cheating. More information about these two can be accessed here: http://en.lichess.org/qa/192/what-is-this-player-artificially-increasesdecreases-their-rating
A cheater's profile will have a header saying, "This player uses chess computer assistance" (or This player artificially increases/decreases their rating). This flag will be visible in public to everybody except the cheater.
2. Can I use an engine in casual games (or against stockfish/the puzzles/opening training)?
A: Yes. You may ONLY IF YOUR OPPONENT KNOWS AND YOU HAVE THEIR EXPLICIT PERMISSION TO DO SO. If someone wants to play a computer, they can play vs. AI. They should have expectation that they're playing a human if they accept a human's challenge. You can use an engine against the lichess built-in AI ("play with the machine" on homepage) if you please; games against the computer are never rated. Similarly, using an engine to solve a puzzle (or help you in the opening training) is not against the rules and you will not be marked as a cheater. But, should you use an engine for the training puzzles/openings, you'll only be cheating yourself.
3. Is it cheating if I use an opening book for correspondence games?
A: You may use an *opening book* or *games database* for rated and unrated CORRESPONDENCE games. You can use a *book* and not an engine.
4. How are cheaters identified?
- 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.
5. I think my opponent (or any registered member) cheated. What do I do?
A: First, please request a computer analysis and check yourself: if your opponent had 7 blunders, 3 mistakes and 27 inaccuracies, it's very unlikely s/he cheated. However, if your opponent has 0 blunders, 0 mistakes, 0 inaccuracies and a very low centipawn loss, it's more probable that your opponent cheated.
If, after viewing the game analysis, you still think your opponent has cheated, please submit a report against the user. You can report them by clicking their name and clicking the report button on their profile. Alternatively, you can use the report form: http://en.lichess.org/report?username=
... Please do NOT post about it in the forum; your post will be deleted.
If you think an anonymous player cheated, please don't send us the game. Anonymous players can't play rated games. Also, we can't identify anonymous players and consequently can't do anything about it.
6. Can I get my rating points back if I played against a cheater?
A: Yes, there are rating refunds. For the rules about when you are eligible for a rating refund, see this post: lichess.org/qa/3185/when-am-i-eligible-for-the-automatic-rating-refund-from-cheaters
7. I was marked as a cheater/sandbagger/booster even though I didn't cheat. What do I do?
A: It is possible, though not very likely, that you were incorrectly flagged as a cheater. You can email lichess at firstname.lastname@example.org arguing your case. As in real life, ignorance isn't an excuse for being marked. Again, please don't plead your innocence in the forums.
8. Can cheaters play in tournaments?
9. If someone's caught cheating during a tournament, what happens?
A: They get expelled from the tournament.
10. I'm going to create a new account because I've been marked. Why shouldn't I?
A: You shouldn't create a new account because you marked. You're only allowed one account. If you believe you've been incorrectly marked, refer to point 7. If you really need more than one account, and you're going to use it for legitimate purposes, just ask. You can email email@example.com with your situation.
11. Someone keeps accusing me of cheating. I didn't cheat... What do I do?
A: Don't worry about it. If you aren't cheating, continue as you were; nothing will happen.
If someone starts accusing you (or being annoying), just click the little tick in the chat box so you can't see what they're saying. If they seriously think you're cheating, they'll report you. You can, additionally, report them as a troll.
12. Is it cheating when people abandon their games and/or when they let their time run out?
A: If your opponent frequently aborts and/or leaves games (without resigning/drawing/winning/losing) then lichess' "playban" system will temporarly ban them from playing games for a set amount of time. The more someone leaves/aborts, the longer the ban is.
If your opponent lets their clock run down for whatever reason - usually because they're losing, the mods can't do anything about that. It's bad sport not cheating. See this link for more information: http://en.lichess.org/qa/547/what-to-do-about-players-that-time-down
However, if it's consistent (i.e.: they join games for the purpose of letting their time run out), that could be considered artificially decreasing the rating.
13. If someone else uses my account to play, is that cheating?
A: It is not permitted to give anyone access to your account. If you do, and they play rated games, then yes: that is cheating. If they play casual games then, no, that's not cheating.
If they play rated games on your account, it's cheating because it's someone else gaining/losing rating points on someone else's account.
More information on this matter here: http://en.lichess.org/qa/986/am-i-allowed-to-share-my-account-with-someone-else
* If you have a question about cheating, please add a comment below and this answer will be updated with your question and your answer.