Alternative Chess. Last changed 27 August 2026.
Alternative Chess is a chess app run by one person. These are the rules of using it. Using the app means accepting them. If you do not accept them, do not use the app.
The app is free. It never asks for money, there is nothing inside it to buy, and it carries no adverts.
You do not need an account. A player who never signs in can play every mode, against the computer, against somebody on the same phone, and against somebody on another device. An account exists so a rating and a display name can follow you between devices, and nothing else depends on it.
When you play a person, play the moves yourself. Using a chess program to choose your moves against another person is not allowed. The computer opponent inside this app is a different thing and is the point of it: play it as much as you like.
In the disguised queen mode each player secretly turns one pawn into a queen, and the server never sends a player the other player's choice. That secret is the whole mode. Trying to get it any other way is not allowed — reading the traffic between the app and the server, altering the app, or attacking the server.
A display name is shown to the people you play. Do not use one that is abusive, that impersonates somebody else, or that you would not want shown to a stranger. An account using such a name may be removed without warning.
The server that carries games between devices is small and is run by one person. It may be restarted, changed, or switched off at any time, with no notice, and a game in progress can end that way. Do not attack it, do not try to overload it, and do not try to take a seat in a game that is not yours.
The app is provided as it is. There is no guarantee that it works, that it is available, or that it is fit for any particular purpose. As far as the law allows, the person who runs it is not liable for any loss arising from using it.
You can stop at any time. Delete my account, in Settings, removes an account and everything the accounts server holds for it. The person who runs the app may remove an account that breaks these rules.
The app is not for children under 13. Making an account needs an email address, and this project does not knowingly keep an account for anybody younger. Playing without an account collects nothing and is not restricted this way.
The app itself is closed source. The chess engine inside it is not: it is Fairy-Stockfish, it is under the GPL-3.0 licence, that licence travels inside the app, and its source is published. Nothing here claims any right over it. The row at the foot of Settings that names the engine leads to the licence and to the source.
These rules may change. The version that applies is the one in the app and at chess.furkankucuk.net/terms.html, and the date at the top of the page says when it last changed.