Terms of Service

1. This agreement

These Terms are a binding agreement between you and Mincho Milev (“we”, “us”) covering the Chess Trainer app for iPhone and iPad and this website (together, the “Service”). By downloading, installing or using the app you accept them. If you do not accept them, do not use the app.

This agreement is between you and us alone, and not with Apple. Apple is not a party to it and is not responsible for the app or its content.

2. Licence to use the app

We grant you a limited, non-exclusive, non-transferable licence to use the app on any Apple-branded product that you own or control, as permitted by the Usage Rules in the Apple Media Services Terms and Conditions, and subject to Section 3 below.

3. The GNU GPL comes first

Chess Trainer is free software. It is licensed under the GNU General Public License, version 3 or later, and its complete corresponding source code is published at https://github.com/minchopm/chess-trainer.

The reason is worth stating rather than burying: the app links Stockfish, the chess engine, which is itself licensed under GPLv3. A work that includes it must carry the same terms.

Accordingly, and notwithstanding anything else in this agreement:

• Your rights to use, copy, study, modify and redistribute the software and its source code are governed by the GPLv3, not by Section 2.
• Where any term of this agreement conflicts with the GPLv3 as it applies to the software, the GPLv3 governs, and the conflicting term does not apply to that software.
• Nothing here is intended to, or does, impose any further restriction on the rights the GPLv3 grants you.

The parts of the Service that are not the software — our name, the Chess Trainer wordmark, the app icon and the artwork and text on this website — are not covered by the GPL and remain ours. You may not use our name or marks to suggest that a modified version comes from us.

Paying for the app on the App Store buys you a compiled, signed, supported build and supports the work. It does not buy the software, because the software was already free. The GPL has never forbidden charging.

4. What the app does and does not promise

Chess Trainer is a training tool. It estimates your strength with its own internal ratings, which run several hundred points above over-the-board ratings and are not, and are not presented as, FIDE, national federation or Lichess ratings. They measure your progress against yourself.

Engine evaluation, coaching feedback and puzzle solutions are produced by software and can be wrong at the margins. We check them — every endgame drill’s stated result is verified against a deep search, every mined puzzle is checked twice, and imported puzzles are sampled — but we do not warrant that every position, evaluation or explanation is perfect.

5. Purchases, subscriptions and renewals

The app is free to download. Playing against the engine and playing another person over Game Center are free and unlimited. The training modes are metered on a free account and unlimited with Chess Trainer Pro, available as:

• a monthly auto-renewing subscription at $3.99 per month; or
• a one-off unlock at $49.99, which does not renew.

All prices are shown in the App Store in your local currency and are set there. All purchases are made through, billed by and fulfilled by Apple, under the Apple Media Services Terms and Conditions.

How the subscription renews

• Payment is charged to your Apple Account at confirmation of purchase.
• The subscription renews automatically for the same period unless you turn off auto-renewal at least 24 hours before the end of the current period.
• Your account is charged for renewal within 24 hours before the end of the current period.
• You can manage or cancel it in your Apple Account settings — Settings → your name → Subscriptions — at any time. We cannot cancel it for you, because we never had it.
• Cancelling stops future renewals; it does not shorten the period you have paid for.

Refunds

Refunds are handled by Apple under its own policy, at reportaproblem.apple.com. We cannot issue refunds for App Store purchases. If something is broken, tell us — we would rather fix it than have you ask Apple for your money back, but the choice is yours and the route is Apple’s.

Changes to the free allowance

The free daily allowance — currently five tactics puzzles, one Rush run, and three each of the positional exercises, endgame drills and games to judge — may change. Unlimited play against the engine and against a person will not become a paid feature.

6. How you may use it

You agree not to:

• use engine assistance or any external help during an online game against another person;
• interfere with, disrupt or attempt to manipulate the online rating system or another player’s match;
• use the Service in any way that breaks the law where you are, or that infringes anyone else’s rights.

Online play has no server of ours, both devices run the rules, and a peer sending an illegal move gets a dropped packet rather than a moved piece. The online rating is therefore honest rather than tamper-proof: a modified build could lie to it. We say so plainly because the alternative would be pretending otherwise.

7. Third-party components and terms

The app includes third-party software, listed with its licences on the Licences page — most importantly Stockfish (GPLv3) and puzzle and game data from the Lichess database (CC0). You agree to comply with any applicable third-party terms when you use the app. Those licences run in your favour as well as ours.

8. The terms Apple requires

Apple requires every app distributed on the App Store to carry the following terms. They apply in addition to everything above.

Acknowledgement

You and we acknowledge that this agreement is concluded between you and us only, and not with Apple, and that we, not Apple, are solely responsible for the app and its content.

Scope of licence

The licence granted to you for the app is limited to a non-transferable licence to use the app on any Apple-branded products that you own or control, and as permitted by the Usage Rules set out in the Apple Media Services Terms and Conditions — except that the app may be accessed and used by other accounts associated with you via Family Sharing or volume purchasing, where offered. Section 3 above applies to the software itself.

Maintenance and support

We are solely responsible for providing any maintenance and support services for the app, as specified in this agreement or as required under applicable law. You and we acknowledge that Apple has no obligation whatsoever to furnish any maintenance and support services for the app.

Warranty

We are solely responsible for any product warranties, whether express or implied by law, to the extent not effectively disclaimed. In the event of any failure of the app to conform to any applicable warranty, you may notify Apple, and Apple will refund the purchase price (if any) for the app to you. To the maximum extent permitted by applicable law, Apple will have no other warranty obligation whatsoever with respect to the app, and any other claims, losses, liabilities, damages, costs or expenses attributable to any failure to conform to any warranty will be our sole responsibility.

Product claims

You and we acknowledge that we, not Apple, are responsible for addressing any claims of yours or any third party relating to the app or your possession and use of it, including but not limited to: (i) product liability claims; (ii) any claim that the app fails to conform to any applicable legal or regulatory requirement; and (iii) claims arising under consumer protection, privacy or similar legislation, including in connection with the app’s use of the HealthKit and HomeKit frameworks — which this app does not use.

Intellectual property rights

You and we acknowledge that, in the event of any third-party claim that the app or your possession and use of it infringes that third party’s intellectual property rights, we, not Apple, will be solely responsible for the investigation, defence, settlement and discharge of any such intellectual property infringement claim.

Legal compliance

You represent and warrant that you are not located in a country that is subject to a U.S. Government embargo, or that has been designated by the U.S. Government as a “terrorist supporting” country; and that you are not listed on any U.S. Government list of prohibited or restricted parties.

Developer name and address

Questions, complaints or claims with respect to the app should be directed to Mincho Milev at mincho.milev@gmail.com. We will supply a postal address on request.

Third-party beneficiary

You and we acknowledge and agree that Apple, and Apple’s subsidiaries, are third-party beneficiaries of this agreement, and that upon your acceptance of it, Apple will have the right (and will be deemed to have accepted the right) to enforce it against you as a third-party beneficiary of it.

9. Disclaimer

Except as required by law and except as stated in Section 8, the Service is provided “as is” and without warranty of any kind, express or implied, including the implied warranties of merchantability and fitness for a particular purpose. This is the same disclaimer the GNU GPL carries, and it is meant literally: the software is given to you free, with its source, and without a promise that it is perfect.

Nothing in this agreement excludes or limits any liability that cannot lawfully be excluded or limited, including liability for death or personal injury caused by negligence, or for fraud. If you are a consumer, you have statutory rights that this agreement does not affect.

10. Liability

To the extent permitted by law, our total liability to you arising out of or in connection with the Service is limited to the greater of (a) the amount you paid us for the app in the twelve months before the claim arose, and (b) ten United States dollars. We are not liable for indirect or consequential loss, loss of data stored only on your device, or loss of rating.

11. Termination

You may end this agreement at any time by deleting the app. Your rights under the GNU GPL to the source code survive, because they were never ours to withdraw. We may end it if you breach it materially, which in practice means using the app to attack the Service or another player.

12. Changes to these terms

We may update these Terms. The effective date at the top of this page changes when we do, and material changes will be noted in the app’s release notes. Continuing to use the app after a change means you accept it; if you do not, delete the app.

13. Governing law

These Terms are governed by the laws of Bulgaria, without regard to conflict-of-law rules, and the courts of Bulgaria have non-exclusive jurisdiction. If you are a consumer resident elsewhere in the European Union or the United Kingdom, you keep the protection of the mandatory consumer law of your country of residence and may bring proceedings there. The GNU GPL, where it applies, is interpreted on its own terms.

14. Contact

mincho.milev@gmail.com — or open an issue at the project’s issue tracker.

See also: Privacy Policy · Licences & attribution