Tachiyomi vs TachiyomiJ2K: The Same Reader With a Different Library

This is a comparison between an app and a fork of that app, which means most of what you would normally compare is identical. Same codebase origin, same Apache 2.0 licence, same extension system, same Android 6.0 floor, roughly the same size.

What TachiyomiJ2K changed is the part you look at every day: the library screen, and how the reader responds to your thumb.

That is a smaller difference than a version number suggests and a bigger one than it sounds, because a manga reader is mostly a browsing interface with a page viewer attached. But there is a larger fact sitting behind both of them, and it should shape the decision more than either interface does.

The specs side by side

Nothing in the top half of that table decides anything. The rows that matter are library view, custom tap zones, and the two backup-compatibility rows — those are the entire case for the fork.

The row worth reading twice is the last-but-one. Both require you to find and paste extension repository URLs before either app can search anything. The fork did not fix that, and it is the step where most people give up.

What the fork actually changed

TachiyomiJ2K is Jays2Kings' redesign of the same reader. Three things are genuinely different.

The library is built around cover art. Large, edge-to-edge artwork with details that expand in place rather than pushing you to a separate screen. If you have a hundred titles and you navigate by remembering what a cover looks like — which is how most people actually navigate a manga library — this is faster than a dense grid of thumbnails. If you navigate by title text, it is not.

Tap zones and page swiping are configurable. You decide which parts of the screen advance, go back, or do nothing, and how swipes behave. This matters more than it sounds for left-handed reading, for right-to-left titles, and for anyone who keeps accidentally skipping pages.

The downloader is multi-threaded and includes a storage purge. Chapters download in parallel rather than one at a time, and there is a built-in way to clear what you have already read instead of watching an offline library quietly consume several gigabytes.

Tracker sync runs automatically. MyAnimeList and AniList progress updates as you read, without a manual push.

Everything else — sources, extensions, backups, the reading engine itself — is the Tachiyomi behaviour you already know.

What neither one changed

Tachiyomi and its forks all share the same architecture, and it has one consequence worth stating plainly.

Neither app hosts anything. They are clients that fetch pages from third-party sites and parse whatever HTML those sites return. When a site changes its layout, adds an anti-bot check, or moves an endpoint, the extension for that source stops working — and it stays broken until somebody ships a fix.

That makes maintenance status the single most important property of a reader in this category, ahead of every interface feature. It is also why "which fork has the nicest library screen" is a less useful question than it looks.

Upstream Tachiyomi ended in January 2024. Its own release notes point at Mihon as the continuation. Forks that predate that decision have each taken their own path since, so before you move a library into any of them, open the project's repository and look at when something last shipped. That check takes thirty seconds and it is worth more than this entire comparison.

Backups are the reason you can try both

The fork reads Tachiyomi and Mihon backup files. That compatibility is what makes this a low-risk experiment rather than a commitment.

The sequence is: open your current app's settings, export a backup, save the file somewhere that is not the app's own folder, install the other one, import. Your library, categories and tracking links come across. Both apps can sit on the device at once, so nothing needs uninstalling until you have decided.

Two cautions. Reading positions and history are less reliable than the library itself, so expect to lose your place in anything you are partway through. And the backup file is the only copy of your library that exists outside the app — if you uninstall before exporting, there is nothing to recover, because none of this is stored on a server anywhere.

Which one to install

You want the cover-first library and custom tap zones. TachiyomiJ2K. That interface is the entire reason the fork exists, and no other reader here has it.

You have an existing Tachiyomi library and want it maintained. Mihon. It is the continuation the original developers named, it keeps the interface and the extensions, and it is not in this catalogue so there is no page to link — check the project directly.

You are installing a manga reader for the first time. Neither. Both need extension repository URLs pasted in before they do anything, and Kotatsu ships its sources built in so search works the moment you open it. That comparison covers the trade-offs in full.

You read your own CBZ files. The Tachiyomi lineage, including J2K. Local file support is the one thing Kotatsu does not do.

You are on an old phone. Either — both run on Android 6.0, which is a low floor by 2026 standards.

Before you install

Both arrive as APKs rather than through the Play Store, and both bring the same two stops.

A refused install with "App not installed" is almost always a signing-key conflict: the original and the fork are signed by different people, so one cannot replace the other in place. The fix is to export a backup, uninstall, install the new one, and import — covered in full in the "App not installed" guide.

Play Protect will also warn about an unknown developer. That warning describes who signed the file, not what is inside it, which is exactly what you would expect for an independently built open-source app.

Check the SHA-256 against the value the project publishes before you install either one. For the wider field, the Android manga reader roundup covers seven apps including both of these.

The short version

TachiyomiJ2K is Tachiyomi with a cover-first library, configurable tap zones, a faster downloader and automatic tracker sync. It reads your existing backups, so trying it costs one export and one import.

Both still require extension repositories added by hand, and both descend from a project that stopped in January 2024.

If the interface is what you are after, take the fork. If you want a reader that is being looked after, that is a different question — and the answer is Mihon or Kotatsu, not either app on this page.

Every app named here resolves to a page in the FileCobra catalogue — the build fails if one does not. Versions, package sizes and system requirements are read from that catalogue rather than written by hand. Where our ingestion worker has fetched a release itself, it records a SHA-256 of the exact file we serve and publishes it on the app’s page. We do not run an antivirus lab: where a VirusTotal report exists we link it, and where none exists we say so rather than imply one.