Multiplayer Chess

Are multiple accounts allowed in multiplayer?

Multiple multiplayer accounts are allowed but not encouraged. We recognize that there are legitimate reasons for players to have more than one account. However, using multiple accounts to inflate your score or for other nefarious purposes is not allowed, and such accounts may be removed without warning.

What are playing areas?

After logging into multiplayer mode, you will be presented with a list of playing areas from which you must select (enter) one in order to play.

Playing areas are also called “lobbies” in multiplayer games. Simply put, they are virtual gathering places where players can meet and challenge each other. Playing areas can have some restrictions, for example, one of them is reserved for new players.

Upon entering a playing area, you will see a list of available players. When you click on a player’s name in the list, you invite them to play. Or you can simply wait until you are invited.

How can I set an avatar (profile photo) in multiplayer?

You can use the Gravatar service to add an avatar. Gravatar stands for Globally Recognized Avatar and it’s a free service from WordPress, the organization that maintains the WordPress software that powers over a third of the world’s web sites. Gravatar works by linking an email address to a public profile picture.

To add a photo, first you need to create an account:

• Visit www.gravatar.com
• Click on the big Create Your Own Gravatar button.
• A simple account sign up form will be shown. Enter the same email address you’re using with SparkChess and a password. When you submit the form, you’ll receive a confirmation email. Click the Activate Account button on the email.

Now that you have your account, go to gravatar.com again and login from the top right. After login, you’ll see a page with the title Manage Gravatars and the text “Whoops, looks like you don’t have any images yet! Add one by clicking here!” Click on the link and follow the instructions.

If you don’t want a photo, our own system will generate a random profile image for you.

Why do I need the newest version to play in online multiplayer?

We are continuously improving SparkChess in all its areas: the AI chess engine, the multiplayer service, the user interface, the additional tools and so on.

The multiplayer service is particularly sensitive because of the complex interactions and also because a small number of players will always try to cheat their way into the leaderboards.

Whenever we update the multiplayer functionality, we need to consider how two players with different versions will interact. To give you a very simple example, if one player has Chat capability but the other doesn’t, what do we do? Do we let the chat-enabled player send messages to the other one, even though those messages will never be received?

Most cases are more difficult, for example when a move needs to be resent due to a client disconnect.  Even more complicated, when we discover a way to stop cheaters, we may need to effectively ban all old versions.

We try to keep these breaking changes to a minimum and even then we give a few months of transition period, but we can’t support old versions indefinitely.

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 has had 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. Guest players cannot reconnect, so it’s best to avoid playing as a guest.

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.

Can I play correspondence chess?

Yes, correspondence chess support has been added in 2024, in SparkChess 18. See the specific questions and answers for details.

How does filtering work in multiplayer?

Currently the following filters are available:

• by score: with this filter enabled, only players within 10% of your score will be shown. So if you have 1000 points, you’ll see only players with at least 900 points and at most 1100 points.
• by subnet: The filtering is done by IP address. Only players with IP addresses from your “virtual neighborhood” are shown (technically speaking it’s a Class-C subnet). This usually means only players from the same building or block, although it depends on your Internet provider. This mode is perfect when you want to play with a coworker or at home with another person in the same house.
• by country: only players determined to be in the same country as you are shown. This method may not be always available. Players who’ve just created accounts may not have their country determined yet.

We should mention that your location (both the IP and the country) are safe. Another player cannot learn your location.

Did my account disappear?

Free accounts may be removed if unused for prolonged periods. From time to time we purge inactive accounts. The “grace period” is dynamic and calculated based on many factors. We do want to reward active users to conserve resources (storage is not free and having a few GB of unused accounts doesn’t help); we also need to backup the databases and maintain them, which requires more CPU power.

Accounts may also be removed without notice if they contain offensive names.