Question 1

What is OpeningNinja?

Accepted Answer

OpeningNinja is a chess opening trainer that helps you memorize and practice your repertoire. Import your PGN files, and OpeningNinja will quiz you on the moves, track your accuracy, and help you identify weak spots in your preparation.

Question 2

How do I add openings to practice?

Accepted Answer

Go to the Openings page and click "New Opening". You can paste PGN text directly or import a .pgn file. OpeningNinja will automatically extract all the lines and variations for training.

Question 3

Do I need an account to use OpeningNinja?

Accepted Answer

No! OpeningNinja works completely offline without an account. All your data is stored locally on your device. Creating an account is only needed if you want to sync your repertoire across multiple devices.

Question 4

What is the "Choose Your Move" step?

Accepted Answer

When your PGN gives your own side more than one move from the same position, OpeningNinja can't tell which line you actually want to play — so it asks. The "Choose Your Move" step walks you through each of these forks and you pick the move to train. Your opponent's alternatives are always kept, each becoming a separate line to practice against.

Question 5

Can I edit lines inside the app?

Accepted Answer

Not directly — and that's by design. Your PGN file is the single source of truth. To change a line, edit the PGN in your own editor or database, then open the opening and click "Update PGN". OpeningNinja re-parses the file and automatically detects any new lines. Note that re-importing resets training progress for that opening.

Question 6

What are the different training modes?

Accepted Answer

There are three modes: Random (lines shuffled for true recall testing), Structured (lines grouped by variation for systematic learning), and Priority (lines you haven't trained yet first, then the ones you miss most).

Question 7

What is Perfect Mode?

Accepted Answer

Perfect Mode requires you to complete every line without mistakes. If you make an error, the line restarts from the beginning. It's great for building muscle memory and ensuring you truly know each variation.

Question 8

How does the priority system work?

Accepted Answer

OpeningNinja tracks which lines you've practiced and how accurate you are. Priority mode puts lines you haven't trained yet first, then ranks the rest so the ones you miss most — or haven't reviewed in a while — come first. With no history it simply follows the structured order and adapts as you train.

Question 9

Where is my data stored?

Accepted Answer

By default, all your data (openings, training history, settings) is stored locally in your browser using IndexedDB. This means it works offline and your data stays on your device.

Question 10

What happens if I clear my browser data?

Accepted Answer

If you clear your browser's cache or site data, your locally stored openings and training history will be deleted. If you have a Pro subscription with sync enabled, you can restore your data by signing in again on any device.

Question 11

My openings disappeared - what happened?

Accepted Answer

There are several reasons your data may have been lost: you may have cleared your browser data, uninstalled the app, or — most commonly — your browser automatically cleared storage to free up space. Many browsers do this without warning when your device is low on storage. Unfortunately, locally stored data cannot be recovered. To protect against data loss, consider upgrading to Pro which syncs your repertoire to the cloud and lets you restore it on any device.

Question 12

Can I export my openings?

Accepted Answer

Yes! You can export any opening back to PGN format. This is useful for backups or transferring your repertoire to other chess software.

Question 13

Can I share my openings with others?

Accepted Answer

Yes. From an opening you can generate a share link and send it to anyone. They can open it and clone the opening straight into their own account to train it themselves. Share links expire after 7 days.

Question 14

What features require a subscription?

Accepted Answer

The core training features are free. A subscription unlocks cloud sync across devices, advanced statistics, and priority support. Check our pricing page for current plans.

Question 15

Can I cancel my subscription?

Accepted Answer

Yes, you can cancel anytime. Your subscription will remain active until the end of the current billing period. After that, you'll still have access to free features.

Question 16

What happens if I delete my account?

Accepted Answer

Deleting your account is permanent and cannot be undone. All your data will be removed, including your openings, training lines, training history, and statistics. If you have an active Pro subscription, it will be canceled immediately without a refund. Your local data on other devices will remain until you clear it manually.

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