Privacy & terms

Short version: these are practice games to help me learn Chinese, now shared with you! You can optionally provide your email address to maintain your practice history and statistics. Nothing is sold, shared, or used to advertise to you. I won't send you any spam. You will get an email with a sign-in code or link.

Who runs this

This site (ltns.brianychang.com) is run by me, Brian Chang, as a personal, non-commercial project. Questions or requests about your data: byc@brianychang.com.

What is collected, and why

• Email address (optional). It identifies your account, so your practice history can be saved and progress can be shared between your devices. It is also where a sign-in code is sent to confirm your address on a new device. That code is the only message this site will send you, unless otherwise legally mandated. We will send no newsletters, no marketing. You can play as a guest instead and give no email.
• Display name. Shown to other players in a shared game lobby.
• Practice history. Which numbers, forms, or sentences you have seen, whether you knew them, how long you took, and which words you looked up while reading. The app uses it to choose what to show you next, and to show you where the work is.
• Reports. If you flag a card or a sentence as wrong, the content, your answer, and your display name are kept so the error can be fixed.
• Your IP address, to rate-limit abuse — too many sign-ins or reports at once. It is kept only for as long as the limit it enforces: a counter that resets within the hour, and, against a sign-in code you have asked for, the address that asked, deleted with the code within the hour. It never becomes part of your profile and is used for nothing else.

Aggregated, non-personal statistics are kept to improve the games: how often everyone mishears quatre-vingt-quinze, which voice reads which number worst, which sentence pattern trips people up. They cannot be traced back to you.

What is not collected

No passwords, no payment details, no analytics or advertising trackers, and no third-party scripts of any kind. The site sets no cookies; it keeps your sign-in in your own browser's local storage, which you clear by signing out.

How it is protected

• Your email address is stored encrypted (AES-256-GCM) with a key that is not in the database. Only a keyed hash of it is used to find your account, so the address itself is not readable in the data files. The games' own databases hold no email at all, only an internal id.
• There is no password. Your address is your identity and authentication method. Sign-in by emailed code.

Who can see what

Other players see your display name in a lobby. The person who runs the site can see your email, name, and history to maintain the games and answer requests. No one else has access; nothing is shared with or sold to anyone; the data lives on the site's own web host, on a server in the United States, and is not sent anywhere else.

How long it is kept

• A guest session and everything in it is deleted automatically after 24 hours of inactivity.
• An account is kept until you delete it.
• Multiplayer lobbies are deleted after 24 hours of inactivity.

Your rights

You can, at any time:

• See your history: it is the 统计 (stats) screen.
• Delete your account and every trace of it yourself: on the front page, signed in, use Delete my account. It removes your identity, your history in every game and your lobby records immediately, and it cannot be undone.
• Ask for a copy or a correction, or ask questions, at the contact address above. Requests are answered within 30 days.

If you are in the EU/EEA or the UK this notice is required by the GDPR and the UK GDPR. Your data is transferred to and stored on a server in the United States; the legal basis for processing is your consent, given when you enter an email, and you can withdraw it by deleting your account. Children under 13 should play as a guest rather than enter an email.

Content credits

The vocabulary follows the HSK word lists. Dictionary glosses and pinyin for words outside those lists come from CC-CEDICT, used under CC BY-SA 4.0. Where example sentences are drawn from the Tatoeba corpus they are used under CC BY 2.0 FR, attributed to their Tatoeba contributors. Some sentences are generated for this site and reviewed before shipping; a sentence that reads badly can be reported from inside the app.

Terms, briefly

The games are provided free, as they are, with no warranty of any kind and no guarantee they will keep running or that every sentence in them is correct. Please use the report button when one is not. Don't abuse them (automated play, flooding lobbies, or trying to read other people's data). The Chinese content is assembled for practice and is not a substitute for a course or a teacher.

Last updated: 18 August 2026.