Terms of Service

Using Chess.one means accepting these terms with Underwater Games OÜ, registry code 17486604, Harju maakond, Tallinn, Kesklinna linnaosa, Estonia. Read our Privacy Policy too.

1. Chess.one services

These terms cover online matches, computer games, puzzles, analysis, ratings, leaderboards, social features and memberships on the Chess.one website and applications.

2. Accounts and age

Keep login details secure. Users must be 16 or older, or have parental consent where legally permitted.

Use your own sign-in identity and provide an email address you can access. You are responsible for activity on your account; report suspected unauthorized access promptly.

3. Fair play and conduct

Treat other players respectfully. Harassment, unlawful content, impersonation, spam, hacking and disruption of the service are prohibited.

Play your own moves

During an ongoing game against another person, use your own judgment without outside assistance. This applies to rated, unrated, casual and private games, including games against friends. It applies throughout the game, including your opponent’s turn and periods when you are disconnected. Even assistance with a single move or position can break this rule.

• Do not consult chess engines, AI assistants, opening books, personal opening notes, opening databases or explorers, endgame tablebases, or other resources to help with the ongoing game.
• Do not use evaluations, move suggestions, hints or blunder checks from software, websites, browser extensions or another device. This includes Chess.one’s own analysis tools.
• Do not seek or use advice from another person, including a coach, friend, spectator or stream chat. Do not give another player advice about their ongoing game.
• Do not automate moves or use software to play on your behalf unless Chess.one expressly authorizes that use for the mode or interface concerned.

An opponent’s agreement, or a suspicion that they are cheating, does not permit you to use assistance. Exceptions must be expressly authorized by Chess.one for the mode or activity.

Study, computer play and puzzles

You may use analysis tools for independent study and completed games, provided they do not assist an ongoing game against another person. In computer games and puzzles, you may use the built-in hints, solutions and learning tools offered for that activity as intended.

Outside assistance is permitted for noncompetitive practice that does not submit results for ratings, leaderboards, achievements or rewards. Otherwise, do not use outside engines, advice, looked-up solutions or automation to earn or inflate those results. Playing against a computer does not by itself exempt reward or rating manipulation. Do not bypass the limits or consequences of a built-in hint or solution feature.

Results, accounts and sportsmanship

• Do not arrange results, intentionally lose to lower a rating, boost another account, play against your own accounts, coordinate draws to manipulate standings, or farm rewards through collusion or automation.
• Do not play on someone else’s account or let someone else play on yours without our express permission. Do not evade a restriction or ban by creating, borrowing or using another account.
• Do not misuse chat, draw offers, takeback requests or challenges to harass or distract players. Report suspected cheating privately; do not make public accusations or encourage harassment.

Reviews and enforcement

We may review gameplay, account activity and reports to investigate suspected violations, as described in our Privacy Policy. Where we have reasonable grounds to suspect abuse, we may temporarily restrict play or features while reviewing the matter.

For violations, we may issue warnings, restrict features, suspend or close accounts, correct affected ratings or results, and remove improperly obtained rewards. Serious violations may lead to immediate action without a prior warning. We do not guarantee that every violation will be detected or that every affected result can be corrected.

We may withhold detection methods, confidential reports and information about other users to protect investigations and their privacy, subject to applicable law. This does not prevent you from challenging a decision.

Reports and appeals

Send reports or appeals to support@underwatergames.com. For a report, include the relevant usernames, game links or IDs, and a brief explanation. A report alone does not establish that someone cheated.

If you believe a restriction or sanction was mistaken, contact us from the email address linked to your account where possible. Include your username, the decision you are appealing and any relevant context. A person will reconsider the decision and the information you provide, and we will communicate the outcome. Restrictions remain in place during an appeal unless we tell you otherwise. Your rights under applicable law remain unaffected.

4. Memberships and rewards

Before buying a membership, review the displayed price, billing period, renewal and cancellation conditions. Manage web memberships in membership settings. Stripe handles web payment processing; purchases through an app store also follow that store’s payment rules. Statutory cancellation and refund rights remain applicable.

Diamonds, cosmetic items, achievements and other virtual rewards provide features within Chess.one. They are not money, cannot be redeemed for cash and do not represent a financial investment.

5. Content and permitted use

We grant personal, non-exclusive, revocable access. Service content belongs to us or its licensors; applicable open-source licenses remain effective. You retain your content and permit us to host and display it to operate Chess.one.

Only upload avatars, profile text or other material you have permission to share. Public chess games and profile activity may be displayed to other players and spectators.

6. Availability and responsibility

Maintenance and updates may interrupt access. To the extent legally allowed, we exclude liability for service interruptions and resulting losses. Nothing excludes fraud, negligent personal injury or mandatory consumer rights.

Online chess depends on your device and connection. A disconnection may leave your clock running or result in a loss under the game’s rules. Save any analysis or game exports you wish to keep.

7. Leaving Chess.one

Use account deletion to close your account. Cancel active memberships first. Deletion resigns ongoing games and removes access to your account and progress.

8. Law, changes and contact

Estonian law applies, subject to mandatory local consumer protections. Invalid provisions do not invalidate the rest. Updated terms appear here; material changes will be notified appropriately.

Questions or disputes: support@underwatergames.com.