Reading Tracking and Statistics

Yatsu has a reading tracker that can record how much time you spend reading, how many characters you move through, reading speed, book completion dates, and reading goal progress.

Quick version

If you only want basic reading stats:

1. Open Settings.
2. Open Tracking.
3. Turn Enable Statistics on.
4. Open a book.
5. Use the tracker icon in the bottom-left corner of the reader.

The tracker icon uses these states:

• A red play icon means tracking is paused.
• A pause icon means tracking is running.
• Click the icon once to open the tracker menu.
• Double-click the icon to start or pause tracking without opening the menu.
• Press p in the reader to toggle tracking with the default keybind.
• Press e in the reader to toggle position freeze with the default keybind.

When the tracker is running, Yatsu updates reading time every second and compares your current character position with the previous tracked position. The difference becomes the characters read for the current session.

The character position uses the current book's character counting method. Japanese and Chinese counting is the default; Korean books can use the per-book Character Counting Method in the live appearance panel. See Korean Support for setup details.

What Yatsu Records

For each book and date, Yatsu can store:

• Characters read: the net character-position movement counted by the tracker.
• Reading time: seconds tracked while the tracker is running.
• Reading speed: characters per hour, calculated from characters read and reading time.
• Minimum speed and maximum speed values.
• Book completion data, if the book is marked complete.
• Last modified data used when syncing and merging statistics.

Yatsu also stores reading goals separately. A goal can have a time target, a character target, a frequency, and a start date.

Privacy

Reading statistics stay in browser storage unless you export them or sync the Statistics data type to another storage source. Reading goals work the same way with the Reading Goals data type.

Yatsu Account Settings Sync does not sync reading statistics, reading goals, bookmarks, highlights, or book progress. It only syncs Reader and Tracking settings.

If you sync to an external provider, that provider receives the data types you choose to sync.

Note

Statistics are based on the reader's character position, not on eye tracking or page visibility alone. If you leave the tracker running but do not move through the book, Yatsu will mostly add time, not characters.

Starting and Stopping the Tracker

The tracker only appears in the reader after Enable Statistics is turned on.

When you open the tracker menu, Yatsu pauses tracking while the menu is open. If the tracker was running before you opened the menu, closing the menu resumes it.

The tracker menu contains:

• Current Session: what has been counted since the current tracker session started.
• Today: the current tracking day for the book.
• All Time: all stored statistics for the book.
• Book Completion: completion data, if the book has a recorded completion entry.
• Autoscroller: a temporary row shown while autoscroll data is available.
• Recent History: recent tracking updates, with time and character differences.

The menu actions are:

• Play/Pause: starts or pauses the tracker.
• Update Position: resets the tracker reference point to the current reader position.
• Freeze Position: temporarily protects the current position so a jump or layout change is not counted as normal reading progress.
• Save: flushes pending statistics to the local database.
• Revert Item in Recent History: adds the opposite time and character change for that history entry.

Clicking some tracker values toggles blur for those values. This is meant for screenshots or streaming when you do not want to show exact numbers.

How Time and Characters Are Counted

When tracking is running:

1. Yatsu starts a one-second timer.
2. Every tick, it checks the current character position.
3. It calculates the character difference since the last tracked position.
4. It adds elapsed time and the character difference to the session, today's entry, and the all-time entry.
5. It periodically saves pending changes, and it also saves when tracking is paused.

Reading speed is recalculated from the stored values:

reading speed = characters read / reading time, shown as characters per hour

If a reading update crosses the configured start-of-day boundary, Yatsu uses the boundary to decide which date keys need to be updated.

Yatsu does not count while the tracker is paused. It also pauses or avoids counting in several app flows that can change position without normal reading, such as opening full settings, leaving the reader, using some dialogs, resizing the reader, or using custom reading point controls.

Tracking Settings

Open Settings -> Tracking to configure these options.

Collection & Sync

These settings affect whether statistics exist, how they are stored, and how they merge with synced data.

Setting	Default	What it does
Keep Local Data on Deletion	On	Keeps local statistics when you remove a local book copy. This is useful if you plan to reimport or sync the book later.
Clear Zombie Statistics	Action	Deletes statistics that no longer match a local book. Use it when old deleted-book stats are cluttering the Statistics page.
Overwrite Book Completion	Off	When off, Yatsu keeps the first recorded completion for a book. When on, completing the book again can move the completion marker to the latest completion.
Start Day Hours	0	Changes when a tracking day starts. For example, 4 means reading before 4:00 counts toward the previous day.
Statistics Merge	Merge	Controls how statistics combine during sync. Merge keeps entries by date and prefers newer data. Replace lets the incoming dataset replace existing entries.
Reading Goals Merge	Merge	Controls how reading goals combine during sync. Merge combines compatible goal windows. Replace lets the incoming goal dataset replace existing goals.
Enable Statistics	Off	Shows the tracker in the reader and enables statistics collection.

Tracker

These settings appear after Enable Statistics is on.

Setting	Default	What it does
Tracker Auto Pause	Moderate	Controls focus-based auto-pause behavior. See the next section for the modes.
Open Tracker on Completion	On	Opens the tracker menu after you complete a book, so you can review completion data.
Update on Completion	Off	When completing a book, adds the missing character count between your current position and the end of the book. Leave it off if you do not want book completion to create a large character jump.
Autostart tracker (sec)	0	If greater than 0, the tracker starts automatically after the reader has had no page-change events for that many seconds. 0 disables autostart.
Idle Time (min)	0	If greater than 0, the tracker pauses after this many minutes without page changes, pointer movement, or text selection changes. 0 disables idle auto-pause.
Forward Skip Threshold	2700	If one tick jumps forward by this many characters or more, Yatsu treats it as a skip instead of normal reading. 0 disables this threshold.
Backward Skip Threshold	2700	If one tick jumps backward by this many characters or more, Yatsu treats it as a skip instead of normal reading. 0 disables this threshold.
Threshold Action	Ignore	Appears when either skip threshold is enabled. Ignore keeps tracking but counts the jump as 0 characters. Pause Tracker pauses instead.
Dictionary Detection	Off	Attempts to detect Yomitan/Yomichan or jpdb-browser-reader popups and avoid unwanted auto-pauses while using them. Yomitan detection may require disabling Yomitan's Secure Container setting.
Rollback Statistics on Idle	On	Appears when Idle Time is greater than 0. When on, Yatsu tries to subtract the idle period from the session before pausing. When off, the elapsed idle time can remain counted.

Tracker Auto Pause Modes

Off means Yatsu does not pause just because the tab, window, or focus changes. Idle Time can still pause the tracker if you set an idle limit.

Moderate pauses when the Yatsu page becomes hidden, such as when you switch tabs or minimize the browser. It resumes when the page becomes visible again, as long as the pause was caused by auto-pause and you had not manually paused first.

Strict pauses when the browser window loses focus. It resumes on focus when the pause was caused by auto-pause and you had not manually paused first.

Dictionary Detection changes how popup dictionaries interact with Moderate and Strict mode. With detection enabled, Yatsu tries not to treat dictionary lookup focus changes as a reason to pause. With detection disabled, dictionary popups may pause the tracker under auto-pause behavior.

Reading Goals

Reading goals are configured under Settings -> Tracking -> Goals.

To create or change a goal:

1. Turn Enable Statistics on.
2. Open Settings -> Tracking -> Goals.
3. Click Edit in the Current Goal panel.
4. Enter a time target, a character target, a reading speed target, or a combination of them.
5. Choose the goal frequency and start date.
6. Click Save.

A goal can include:

• Time Goal (Min): target reading minutes.
• Character Goal: target characters read.
• Reading Speed Goal (Ch/h): target reading speed in characters per hour.
• Frequency: Daily, Weekly, or Monthly.
• Start Date: when the goal starts.

Leave all goal values at 0 and save to clear the active goal. If you set a non-zero time, character, or reading speed goal, Yatsu needs a start date so it can place the goal in a window.

Goal frequencies work like this:

• Daily: one calendar tracking day.
• Weekly: seven-day windows based on the goal start day and the configured Start Day Hours.
• Monthly: thirty-day windows from the goal start date.

The tracker menu shows active goal progress when a goal applies to the current day. The Statistics page can also show a goal heatmap when reading goal data exists.

Goal Progress Tracker

The Goal Progress Tracker setting is in Settings -> Tracking -> Goals. It controls the small progress light in the reader footer.

The progress light appears only when all of these are true:

• Enable Statistics is on.
• A reading goal is active for the current day.
• The Goal Progress Tracker setting is on.

The light uses these states:

• Gray: a goal is active, but Yatsu does not yet have enough data for the target currently driving the light.
• Green: the selected target is matching or ahead of the goal.
• Yellow: the selected target is close to the goal, but slightly under.
• Red: the selected target is materially behind the goal.

Click the light to open the progress details popover. The popover shows:

• the current goal window
• which target is driving the light
• time, character, and speed progress for every target included in the active goal
• whether each target is waiting, on track, close, or behind
• how many recent turns and how much tracked time the speed estimate is based on, when a speed goal is set

The Dot tracks control in the popover chooses which target colors the light. Auto is the default: it uses Reading Speed Goal when one exists, then falls back to Character Goal, then Time Goal. You can choose a specific available target instead.

When the light tracks speed, the estimate is based on forward page turns while the tracker is running. Yatsu compares the characters advanced with the tracked time since the previous forward movement, then smooths the most recent samples. Backward movement, large skips, pauses, and tiny samples are ignored so the light reflects current reading speed rather than navigation noise.

Temporary auto-pauses, such as popup dictionary detection, stop adding time to the speed sample but keep the latest light color visible. Manual pauses and navigation discontinuities can still reset the speed sample back to waiting.

The goal progress tracker uses the same local statistics and reading goal data as the tracker. It does not upload extra data by itself. Turn Goal Progress Tracker off if you want to keep the reader footer quieter.

Goal Sync and Maintenance

Reading goals have their own Sync, Edit, and Reset actions in the Reading Goals panel:

• Sync copies reading goals between configured storage sources.
• Edit changes the active goal.
• Reset deletes goals. If you delete goals and want that deletion reflected on another device, do a one-time sync using overwrite/replace behavior.

Statistics Page Controls

The Statistics page is where tracked data becomes readable. It includes a reading heatmap, an optional goal heatmap, title filtering, and a summary table.

Date Range

Open View options on the Statistics page to adjust the range.

Control	What it does
Template	Selects Today, This Week, This Month, This Year, or Custom.
From / To	Sets an exact date range. Changing either date switches the template to Custom.
Start of week	Changes how weekly ranges and heatmap week labels are aligned.
Set to all time for selected book titles	Expands the date range to include all statistics for the currently selected titles.

The Statistics page uses Start Day Hours from Tracking settings when calculating what "today" means.

Activity Breakdown

The activity breakdown controls which values are displayed in the summary table.

Control	Options	Meaning
Time Data Source	Total Time, Average Time, Weighted Time	Chooses which time value appears in the table.
Characters Data Source	Characters, Average Characters, Weighted Characters	Chooses which character value appears in the table.
Speed Data Source	Speed, Min Speed, Alt Min Speed, Max Speed	Chooses which speed value appears in the table.
Primary Aggregation	None, Date, Title	Chooses whether rows are individual date/title entries, grouped by date, or grouped by title.

When aggregation is None, each row is one stored book/date entry. This is the mode where individual rows can be edited.

When aggregation is Date, Yatsu groups selected titles by date.

When aggregation is Title, Yatsu groups selected dates by book title.

For grouped rows:

• Total values are sums.
• Average values are averages across entries with reading time.
• Weighted values weight time and characters against each other, so large reading entries affect the result more than tiny entries.

Sharing a Statistics Image

Open Share -> Social image on the Statistics page to create a PNG from the current activity breakdown.

The image starts from the same filtered data shown in the aggregated activity breakdown. If the page is filtered to This Week, a title subset, or a different aggregation mode, the share image uses that same selection.

In the dialog you can:

• Preview the PNG before saving it.
• Choose which statistics appear in the image.
• Pick a square image with one of the built-in pastel backgrounds.
• Download the PNG or copy it to the clipboard.

Supporters can also add custom title/content statistic rows, reorder those custom rows, choose vertical or horizontal social sizes, use any background color, import a local background image, use a local book cover as the background, adjust fit/fill positioning, add a circular avatar, and show their Yatsu username or a custom display name.

Imported background and avatar images stay in the browser while the dialog is open. They are used only to render the local PNG and are not uploaded or synced.

Safeguards and Actions

The View options drawer includes:

• Export selection: exports the current filtered date/title selection.
• Delete selection: deletes the current filtered date/title selection.
• Export all: exports all loaded statistics.
• Delete all: deletes all loaded statistics.
• Confirm Statistics Deletion: asks for confirmation before statistics deletion.

Deleting local statistics does not automatically delete the same data from another storage source. To push deletions to another device or external source, run a one-time sync with overwrite/replace behavior.

Title Filter

The title filter controls which books contribute to the Statistics page.

It can:

• Search titles by text.
• Select or deselect individual titles.
• Show only titles that have data in the current date range.
• Show only currently selected titles.
• Clear a prefilter when you opened Statistics from a specific book or library selection.

Heatmaps

The reading heatmap shows reading activity by day. The goal heatmap shows reading-goal completion when goals exist.

Each heatmap can show:

• All time data, with year navigation.
• Year data for a specific year.
• Current streak and longest streak summaries.
• Day details when you hover or focus a heatmap cell.

The heatmap layout follows Start of week from Statistics view options.

Syncing and Exporting Tracking Data

Tracking data is included in Yatsu's data types as Statistics and Reading Goals.

Statistics and goals are stored locally first. They can then move through:

• Manual export backups.
• Manual sync between storage sources.
• Auto sync, if you have configured automatic replication.
• External sources such as Drive or another configured storage backend.

The two merge settings matter most when more than one device can change tracking data:

• Use Merge when you want Yatsu to combine local and remote entries and prefer newer entries where they overlap.
• Use Replace when you intentionally want one source to overwrite the other. This is usually the mode to use after deleting statistics or reading goals and wanting that deletion to propagate.

Common Confusing Cases

The tracker is visible, but nothing is counting

Check these first:

• The icon is a pause icon, not a red play icon.
• Tracker Auto Pause has not paused because the tab or window lost focus.
• Idle Time has not paused the session.
• Freeze Position is not active. The bottom-left tracker icon pulses while frozen.
• A skip threshold has not been triggered.
• You are actually moving through the book. Reading time can increase without characters if your position does not change.

A big jump did not count as characters read

That is usually the skip threshold. By default, a jump of 2700 characters forward or backward is treated as a skip. If Threshold Action is Ignore, Yatsu keeps tracking but records 0 characters for that jump. If it is Pause Tracker, Yatsu pauses instead.

Use lower thresholds if you want smaller jumps ignored. Use 0 if you do not want that threshold at all.

Completing a book did not add the rest of the characters

Turn on Update on Completion if you want completion to add the missing characters between your current position and the end of the book.

Leave it off if you use completion as a status marker and do not want it to change character counts.

Stats reappeared after I deleted a local book

If Keep Local Data on Deletion is on, deleting a local book copy keeps its statistics. This is intentional.

Use Clear Zombie Statistics if you want to remove statistics that no longer match local books.

Deleted statistics still exist on another device

Deletions are local until synced in a way that applies deletions to the target. Run a one-time sync with overwrite/replace behavior for statistics or reading goals.

My day changed at the wrong time

Adjust Start Day Hours. For example, if you often read after midnight and want that session counted as the previous day, set the start hour to a later morning hour such as 4.