Why did the game end unexpectedly?

Multiplayer games may end unexpectedly due to connection issues on your – or your opponent’s – side.

Since 2014, the SparkChess multiplayer service is having a measured uptime of 99.999% (that is 5 minutes of unavailability per year). Every day, about 10,000 people connect and anywhere from 30,000 to 50,000 games are being played. Frustrating as it may be, only an insignificant number of them end unexpectedly.

In general, a game will end abruptly when one player can communicate correctly with the server but their opponent can’t.  Unlike real-time FPS multiplayer games for example, chess cannot be fault tolerant. In a real-time game one player may miss one or more updates from the server and still keep playing (often the player sees the enemy “jump” from one place to another). But as chess is turn-based, players must be in perfect sync – one player can’t just move twice or ignore a non-responsive opponent!

A player may miss a server move due to many reasons: a bad internet connection or a browser bug are just some of the culprits. For example, Google Chrome can ignore a move received from the server if the browser tab is not active. Or a player may not be connected to the internet and not realize it as the system still reports it as being up.

If a player is disconnected, the SparkChess Multiplayer Service will attempt to reconnect automatically and resend any move that might have been missed, but this must be done within a certain time window as the opponent can’t wait indefinitely.

If you receive a message that the game is out-of-sync and it has ended, it usually means that there was a miscommunication between you, the multiplayer service and your opponent. Since 2018 we decreased the chances of an Out-of-Sync to negligible values.

If you lost any points due to a game ending unexpectedly, please contact us mentioning your username, your opponent’s username, the date & time the match took place and the number of points you lost.