Frequently Asked Questions¶
Getting started¶
What should I read first?¶
If you are new to Yatsu, start with Using the Reader. It explains the reader controls, page movement, bookmarks, appearance settings, tracking controls, and why some controls only appear for certain books or modes.
If you are setting up sync or moving between devices, read Yatsu Accounts and Settings Sync, then Statistics and Sync or Google Drive Sync, depending on what you are trying to sync.
Do I need a Yatsu account?¶
No. You can use Yatsu without signing in.
A Yatsu account is mainly useful for Settings Sync, which can sync Reader and Tracking settings between devices. It does not replace Google Drive, OneDrive, local browser storage, or manual backups.
See Yatsu Accounts and Settings Sync for details.
What does Settings Sync actually sync?¶
Settings Sync syncs Reader and Tracking settings, such as appearance, reading mode, text style, layout preferences, navigation preferences, and tracking preferences.
It does not sync books, book progress, bookmarks, highlights, reading statistics, reading goals, storage sources, cloud credentials, data settings, or uploaded font files.
If you want statistics, streaks, progress, highlights, or reading goals to move between devices, use storage sync with the same Google Drive, OneDrive, or other storage source on each device.
Why did my synced font setting not work on another device?¶
Built-in fonts and Google Fonts can sync as settings. Uploaded font files stay on the device where you uploaded them.
If a synced custom font choice depends on an uploaded file, upload that same font file on the other device too.
Books, storage, and sync¶
Where are my books stored?¶
It depends on the storage source you use.
Books imported into Browser storage live in the current browser profile on the current device. Books from Google Drive or OneDrive live in that external storage source, with local copies or cached data kept in the browser as needed.
Browser storage is convenient, but it is still controlled by the browser and device. Keep backups or sync important books somewhere else.
Can I rely on browser storage as my only copy?¶
I do not recommend it.
Browser storage works well for local and offline reading, but browser cleanup, site data deletion, profile changes, or device problems can remove it. If a book or progress record matters, export it or keep it in an external source too.
I can't turn off persistent storage¶
This is normal if your browser has granted persistent storage to Yatsu.
Yatsu uses the browser's Storage API. The app can ask the browser to make its local storage persistent and can check whether that browser setting is currently active, but browsers do not provide a matching way for a website to revoke it from inside the app. If you click Off after the browser has granted persistent storage, Yatsu checks the browser state and shows On again.
Persistent storage means the browser should avoid deleting Yatsu's local data automatically when it needs to free space. It does not upload your data anywhere.
To turn it off, use your browser's site settings for Yatsu and remove or revoke storage for app.yatsu.moe. You can also clear site data for Yatsu, but read the warning below first.
Warning
Clearing site data can remove local books, settings, progress, and cached data stored in the browser. Export anything you want to keep first, especially if you use Browser storage as your main library.
Browser labels differ, but look for one of these areas:
- Site settings or permissions
- Privacy and security
- Cookies and site data
- Storage used by this site
After revoking or clearing storage, reload Yatsu. The Persistent storage setting should no longer show as enabled.
How do I delete all local Yatsu data from this browser?¶
Open Settings -> Data -> Advanced, then use Danger Zone ->
Delete all local data. Yatsu will ask you to type I am absolutely sure
before the final Delete button becomes available.
This removes local Yatsu data in the current browser profile, including local books, reading state, reading goals, settings, caches, storage-source credentials, and local account session data. It does not delete files in Google Drive, OneDrive, a filesystem folder, synced settings stored in your Yatsu account, or the Yatsu account itself.
If the browser blocks part of the cleanup, use your browser's site-data settings
for app.yatsu.moe to remove anything left behind.
Can I use Yatsu offline?¶
Yes, but only for data that is already on the device.
Open Yatsu while online, open the books you want available offline, and turn on Full Offline Use if you want the app shell saved for offline PWA use. Google Drive and OneDrive still need an internet connection for fetching, listing, importing, exporting, and syncing.
See Using Yatsu Offline for the full checklist.
Do I have to install Yatsu as a PWA for offline use?¶
No. Offline support comes from the browser saving Yatsu's app files and local data. A normal browser tab can work offline after the app has loaded and cached the needed files.
The installed PWA can be nicer on mobile, but it still needs to be opened and prepared while online first.
Why does Yatsu show the browser's offline page?¶
That means the browser did not have enough of Yatsu saved to start the app while offline.
Go online, open Yatsu, turn on Full Offline Use in Settings -> Data if you want full offline PWA behavior, wait until saving finishes, then try offline again.
Do I need the Google Drive setup?¶
Only if you want to use Google Drive as a remote library or sync target.
Most users can use the built-in one-click setup: open the Library, choose Google Drive from the storage picker, and sign in with Google. The old bring-your-own Google Cloud project flow is still available for custom or advanced storage sources.
Yatsu Accounts and Settings Sync do not set up Google Drive book sync for you.
Can I use the same Google Drive folder with Yatsu and ttsu?¶
Yes, but only with an intentionally configured custom storage source.
The built-in one-click Google Drive source uses Yatsu's own yatsu-reader-data folder and is not meant to interoperate with ttsu's default folder. Custom ttsu-compatible sources can still use the shared storage layout. See Compatibility with Ttsu for details and caveats.
How do I move my ttsu library into Yatsu?¶
Export a Zip File backup from ttsu, then import that file in Yatsu with Import -> Import Backup.
Select Book Data, Bookmark, and Statistics in the ttsu export dialog if you want books, current reading positions, and reading history to move. The full walkthrough is in Migrating from Ttsu to Yatsu.
Statistics and tracking¶
Why is the Statistics page empty even though my Drive book has stats?¶
The Statistics page reads from this browser's local database. Google Drive and other external storage sources are sync sources, not the live Statistics page database.
If you want this browser to import Drive statistics, set the source sync behavior to Down or All, open the relevant book, and wait for the opening sync to finish.
See Statistics and Sync for the detailed model.
I read on another device. Why does this device not show the new statistics?¶
The device where you read needs to export the statistics, and this device needs to import them.
For external storage sources, a common setup is Up or All on the reading device and Down or All on the device where you review statistics.
Settings Sync being on does not change this. Settings Sync only moves Reader and Tracking preferences through your Yatsu Account; statistics and streaks move through storage sync.
Does Settings Sync sync reading statistics or goals?¶
No. Yatsu Account Settings Sync does not sync reading statistics, reading goals, bookmarks, highlights, book progress, or books.
Statistics and goals are local first. They can move through manual export, manual sync, or automatic storage sync with Google Drive, OneDrive, or another configured storage source.
The tracker is visible, but nothing is counting¶
Check that the tracker is running, not paused. A red play icon means tracking is paused; a pause icon means it is running.
Also check whether auto-pause, idle pause, Freeze Position, or a skip threshold is active. Reading time can increase without characters if you are not moving through the book.
More troubleshooting is in Reading Tracking.
Why did a big jump not count as characters read?¶
That is usually the skip threshold. By default, Yatsu treats a large forward or backward jump as navigation rather than normal reading.
You can change the forward and backward skip thresholds in Settings -> Tracking, or set them to 0 if you do not want that protection.
Completing a book did not add the remaining characters. Is that expected?¶
Yes, if Update on Completion is off.
Turn on Update on Completion if you want completing a book to add the missing character count between your current position and the end. Leave it off if completion should only mark the book as finished.
Reader behavior¶
Why are some reader buttons missing?¶
Some reader controls only appear when they apply.
For example, Table of contents needs chapter data, Return to current position needs a saved current position, Image gallery needs collected images, and tracking controls need Enable Statistics to be on.
See Using the Reader.
What is the difference between current reading position and bookmarks?¶
The current reading position is the main saved position Yatsu uses for progress and returning later. Bookmarks are separate saved locations that you can name, rename, delete, and jump to.
Use Save current position or Update current position for progress. Use Bookmarks for extra places you want to remember.
Why does my saved position or bookmark feel slightly off?¶
The reader has to choose a text position from the current page or scroll location. If that default point does not match where your eyes treat "current" as being, use Set Point before saving the current position or adding a bookmark.
The custom reading point is explained in Using the Reader.
Language support¶
Why do Chinese characters look like Japanese variants?¶
Yatsu normally uses the language stored in the book file. If a Chinese book is missing language metadata or declares the wrong language, the browser may shape some characters with Japanese glyph forms.
Open the reader's Appearance panel and set Reader content language to Simplified or Traditional for that book. See Chinese Support.
How should I count Korean books?¶
For Korean books, open the reader's Appearance panel and set Character Counting Method to Auto or Korean.
Auto only switches to Korean counting when the book declares Korean or the text looks clearly Korean. If the book metadata is unclear, use Korean directly. See Korean Support.
Integrations¶
How do I use Yatsu with a popup dictionary?¶
Yatsu works with browser-based popup dictionary extensions such as Yomitan and Jiten Reader.
If you use Jiten Reader, update it to version 1.1.0 or newer, reload Yatsu, and open a book at a https://app.yatsu.moe/b URL. Newer Jiten Reader versions include native Yatsu support.
See Using Yatsu with Jiten Reader for setup and fallback steps.
What is Yatsu Whispersync for?¶
Yatsu Whispersync is a Yatsu-compatible userscript build of ttu-whispersync for syncing playback and subtitles with the reader, with optional Anki export support.
Use Yatsu Whispersync if you are trying to align audio or video subtitles with a Yatsu book. You do not need it for normal reading, normal statistics, or Yatsu Account Settings Sync.
Support¶
How do I report a bug?¶
Use How to Report Bugs. It explains how to download a diagnostics bundle, what to include in the report, what the diagnostics ZIP contains, and the privacy notes around that data.
If the bug involves sync or storage, include which source you use, which device changed data, which device failed to see it, and whether refreshing or reopening the book changed anything.