Fair play
Can you use an opening book during online chess games?
The short answer. In daily (correspondence) games, both chess.com and lichess allow opening books and opening explorers. In live games, such as bullet, blitz and rapid, they do not. Engines are not allowed in any rated game. If you play live rated games, use ChessDummy with the corner hidden during the game and do your learning after it ends.
What chess.com says
The chess.com Fair Play Policy allows the Opening Explorer and other opening books in Daily chess only, and not in live play. It forbids engines, tablebases and anything else that shows the best move, in both daily and live games.
What lichess says
Lichess follows the same idea. In correspondence games you may consult opening books and the opening explorer. In real-time games you may not use outside help of any kind. Engine help is forbidden everywhere in rated play.
Rules are updated from time to time. The fair play pages on chess.com and lichess.org are the authority, so read them if you are unsure.
Why the rules draw the line there
Correspondence chess has allowed books for well over a century. With days for each move, looking something up is treated as part of the game. A live game is a test of what you can remember and work out at the board, and a book open beside you changes what is being tested.
What this means for ChessDummy
ChessDummy is a study tool. We would like you to use it in a way that keeps your account safe and is fair to the person you are playing. These are the settings to use.
| Type of game | “During a game” setting | “Show the better move” |
|---|---|---|
| Live rated (bullet, blitz, rapid) | Hide during the game | Off |
| Daily or correspondence | Show the board is within the rules for book moves | Off, because it uses an engine |
| Unrated games against a friend who agrees | Your choice | Your choice |
| Analysis board, bots, finished games | Show the board | On |
With the corner hidden, ChessDummy still follows the game quietly. When the game is over it shows you where the book was left and offers to practice the line. That is the part that makes you better, and it happens after the result is decided.
What ChessDummy never does
- It never moves a piece or submits a move for you.
- It never draws arrows or highlights on the chess.com or lichess board. Everything it shows is on its own small board.
- It never sends your position to a server. The book and the engine run on your own computer.
The safest habit
If you are not sure whether something is allowed in the game you are playing, hide it until the game ends. You lose nothing as a learner. The moment after the game, when you still remember what you were thinking, is the best time to learn an opening.
Frequently asked questions
Is using an opening book cheating?
In daily or correspondence games on chess.com and lichess, no. Books are allowed there. In live games, yes, it breaks the fair play rules of both sites.
Can I use an opening explorer in daily chess?
Yes. Both sites allow opening explorers and books in daily or correspondence games. Engines and tablebases are still not allowed.
Is a browser extension that shows opening names allowed in live games?
Anything that gives you opening book information while a live rated game is in progress is outside the rules. That is why ChessDummy has a “Hide during the game” setting, and why we recommend it for live rated play.
Can I get banned for reviewing my game afterwards?
No. Once a game has finished, you can study it with any book or engine you like. Reviewing finished games is how players improve.