# OpenTaiko, an open-source Taiko no Tatsujin chart player

> OpenTaiko is an open-source rhythm game engine written in C#, descended from TJAPlayer3, that plays .tja chart files and ships with a skinning system and a headless-friendly build for Linux, macOS and Windows. Its rules are unusually clear about what the project will not do, and that includes reproducing commercial game assets.

**0auBSQ/OpenTaiko** — An improved and personalized version of TJAPlayer3-Develop-Rewrite, .tja chart player axed on entertainment and creativity.

- Repository: https://github.com/0auBSQ/OpenTaiko
- Stars: 565 · Forks: 121
- Language: C#
- License: MIT
- Published: 2026-10-22 · Updated: 2026-10-22 · Language: en
- Canonical page: https://hysenlabs.com/projects/0aubsq-opentaiko

## A TJAPlayer3 descendant, not a clone of the arcade game

OpenTaiko is described in the repository as Old TJAPlayer3-Develop-BSQ, a spiritual successor to TJAPlayer3, and the project description calls it an improved and personalized version of TJAPlayer3-Develop-Rewrite, a.tja chart player built on entertainment and creativity. The primary language is C#, and the licence is MIT.

The lineage matters for understanding what the project is. TJAPlayer3 and its forks were community efforts to make the Taiko no Tatsujin drum game playable outside the original arcade and console releases, and OpenTaiko is a continuation of that line rather than a fresh start. The credits section is long and specific about that ancestry, listing Takkkom for the major OpenTaiko features including 1080p support, AI Battle mode and 5P mode, several separate TJAPlayer3 forks by Aioilight, TwoPointZero, KabanFriends, Mr-Ojii and Akasoko, DTXMania and TJAP2fPC, and touhourenren for TJAPlayer3-Develop-Rewrite.

So the project runs.tja chart files, the chart format used by this family of drum games, and the engine is a community-developed renderer and player for them. That is the whole proposition, and the goals section says as much in its first line: multiple fun ways to play Taiko.

The second goal is more customization for better skinning potential, and the stated aim behind it is to make it true that everyone could play Taiko easily at their own style. That phrase is the design brief. A skinning system is not a decoration on this project, it is one of the two things it exists to have.

The third goal is ordinary engineering: optimizations, bug fixes and quality-of-life features.

The last push to the repository was on 2026-10-22, and the recorded releases are 0.6.0.111 from 2026-09-12, 0.6.0.110 from 2026-09-05 and 0.6.0.109 from 2026-08-15, so the project ships roughly every one to two weeks. There are Discord servers, one general and one Japanese, and the documentation is available in Japanese, Chinese and English as separate README files.

## The 60 frames per second line is a hard requirement, not a suggestion

The cautions section is short and the first item under it sets the tone of the whole project.

It is your responsibility to use this software, and the creator will not take responsibility for problems you get from using it. The second line asks you to research before asking people, which is a community-management stance rather than a technical one.

The third is the one that matters for anyone deciding whether to install it: if your PC cannot maintain 60 frames per second stably, it will not work well with the software.

That is a real constraint and it follows from what the game is. A rhythm game judges your input timing against the audio track, so a dropped frame is not a visual stutter but a timing error, and a machine that cannot hold the frame rate produces input latency that the player cannot compensate for. On a rhythm game with scrolling notes, 60 frames per second is also the note scroll speed baseline, so a slower machine would need a different note density and a different rhythm from the same chart.

The consequence for an adopter is that this is a desktop application with a hardware floor, and the floor is not about processor generation or memory. It is about frame pacing, which is a property of the display, the graphics driver and the compositor rather than of the CPU. A machine that struggles at 60 frames per second will struggle more in OpenTaiko than in most games, because it cannot drop frames gracefully without changing the timing.

The fourth caution is about how you obtain the software. From 0.6.0 onwards, you are asked to download and manage OpenTaiko releases through the OpenTaiko Hub, a separate repository at github.com/OpenTaiko/OpenTaiko-Hub. So the release artefacts, and the process of installing and updating them, live outside this repository. That is a deliberate separation, since the Hub is the natural place for a launcher that also has to fetch songs and skins from their own repositories, but it does mean that installing OpenTaiko is a two-repository affair.

## Songs and skins live in their own repositories

The additional notes section explains the content split, and it is worth understanding because it explains why the repository you are reading contains almost no assets.

Songs, skins and different assets are now on different repositories, and only the minimum is provided for development purposes. The content can be obtained either through the OpenTaiko Hub or from the listed repositories: OpenTaiko Soundtrack for the music and OpenTaiko Skins for the skins, covering OWM and Simple Style.

So there are now three repos in play. The engine itself, this one. The soundtrack, which is the audio the charts are timed against. And the skins, which are the visual layer. Plus the Hub, which is the distribution mechanism.

That separation is a good fit for the licensing situation, which the project takes seriously. The team is strongly against the secondary distribution of skins trying to reproduce specific commercial video games, and the non-goals list includes copying other games and commercial licences accurately. Putting skins in their own repository means each skin can be distributed under its own terms, with its own attribution, and a skin that is a reproduction of a commercial game's assets can be excluded without affecting the engine.

The skinning goal is therefore also a governance mechanism. If the community is meant to be able to make their own skins, then the question of which skins exist and under what licence has to be answered somewhere other than inside the engine repository.

For a developer, the practical consequence is that a checkout of this repository is deliberately incomplete. You get the minimum needed to build and work on the code, not the content, and the content comes from the Hub or from the sibling repositories. That is also why the credits section is so thorough about individual skin and asset contributions, listing the people who made the OpenTaiko icon, the 0.6.0 icon, the logo and the default skin assets, along with the translators for Spanish, English, Chinese and Russian.

## Secondary distribution is allowed, and the obligations are spelled out

The editing source code and secondary distribution section is unusually direct, and a commercial user should read it carefully.

OpenTaiko is open source code with an MIT licence. Under the MIT licence you are allowed to make edits or secondary distribute, however this is all your responsibility. And, under the used library's licences, you are asked to include the License folder when editing or redistributing it. The project also asks you to follow the creators' licences and rules for other skins or song packages, and states that the OpenTaiko licence does not apply in that case.

That last sentence is the one to notice. The MIT licence covers the engine code. It does not extend to the skins or song packages you bundle with it, and those carry their own terms. So a fork of OpenTaiko that ships with a particular skin and a particular soundtrack is a distribution of three separately licensed things, and the MIT licence tells you nothing about two of them.

The copyright stance is stated in the section on streams and videos. The author does not support breaking copyright laws and asks that you follow the laws of your country. And the team is strongly against secondary distribution of skins trying to reproduce specific commercial video games.

That is a narrower and more defensible position than a blanket refusal. Shipping an original skin and an original soundtrack is fine under MIT. Shipping a skin that reproduces a commercial game's artwork is not something the project supports, and the enforcement is social rather than technical, since MIT cannot revoke the permission it grants.

The streaming guidance is practical rather than legal. If the website you use for streaming has a tag feature, tagging it as OpenTaiko will avoid confusion and might raise the video as similar content, so it is highly recommended. For a project whose content is close enough to a commercial game that streamers get mistaken for it, that is a sensible request.

This is not legal advice. The point is that the licence boundary in this project is not just the MIT file, it is the MIT file plus whatever the skins and songs you ship carry.

## The non-goals and the rules for filing issues

The rules for posting issues and pull requests are short, and they say more about the project's culture than a code of conduct document would.

You are asked to follow Japan and France copyright laws in the post, which is a peculiar and telling detail, since it names the two jurisdictions the project cares about. Then the practical rule: once you post an issue, write the release version and recreation steps, and if it is a crash, attach the TJAPlayer3.log file.

The log file name is inherited from the TJAPlayer3 lineage, which is a small reminder that this is a fork that has grown rather than one that was designed from scratch. The requirement itself is the sensible part: a crash report without a version, a reproduction path and the log is a report that has to be re-asked for.

Translations are handled by direct contact rather than pull requests. If you want CLang translations, the instruction is to contact the software author on Discord beforehand, and feature requests follow the same route: contact us on Discord beforehand, and if the request is good it might be added.

The feature request policy then states the boundary explicitly. Requests such as please recreate UI/UX as per a named commercial game will be denied and left without answer.

That is the non-goal section restated as a policy, and it is consistent with the earlier line about not copying other games and commercial licences accurately. The difference in approach between this project and the closed-source games it is adjacent to is that it wants to be its own thing with its own skins and its own look, not a reimplementation of someone else's product.

The contributor guidelines are linked, and the README says contributions are welcome with the caveat that you should avoid making changes that conflict with the philosophy. Given the philosophy section spells out that configuration-style constraints for skins and the non-goals, the practical filter on a pull request is fairly clear before you write it.

## Building it from source on each platform

The repository layout shows the source structure and the build entry points, and the README itself gives no command-line install instructions. It points you at the OpenTaiko Hub for released builds, so there is nothing to type for a normal installation. For working on the code, the top-level entries are the guide.

There is a Visual Studio solution, `OpenTaiko.sln`, and a project directory named `OpenTaiko/` alongside it. The `FDK/` directory is the framework the project builds against, and there is a `special/` directory, a CHANGELOG.md, an `.editorconfig` and a `.gitattributes`.

The build scripts are per platform, and they are plain batch files and shell scripts at the repository root: `build.bat`, `build-win-x64.bat`, `build-win-x64-debug.bat`, `build-win-x86.bat`, `build-linux-x64.sh`, `build-osx-x64.sh` and `build-osx-x64.bat`. The naming makes the matrix obvious: two Windows architectures, a debug variant for Windows, and separate scripts for Linux and macOS on x64.

There is also `install-dotnet-sdk.sh`, which is the one script that suggests what the build depends on: the .NET SDK. Given the primary language is C#, that is the expected toolchain, and the presence of a dedicated install script tells you the project expects people building it not to have a suitable SDK already present.

So a source build is a clone, a .NET SDK, and the platform script for your machine, with the FDK bundled rather than fetched. The scripts are named rather than documented in the README, so their flags are not described in the project documentation, and reading them is the only way to know what they do before running them.

One thing worth noting about the release process is the split with the Hub. The engine builds from this repository, but the binaries users install are distributed and updated through the OpenTaiko Hub, which also handles the separate content repositories. That means a change in this repository reaches end users through a two-step path, and the version numbering here, with the triple-numbered form like 0.6.0.111, reflects an internal build counter under a release version rather than a plain SemVer tag.

## Conclusion

OpenTaiko suits someone who wants to play or author .tja charts outside the commercial Taiko no Tatsujin ecosystem, or a developer who wants to study a C# rhythm game engine with a real skinning system, and it suits a modder who wants to write their own skins. It does not suit anyone expecting an accurate recreation of a commercial game, since reproducing other games and commercial licences is an explicit non-goal. Verify first that your machine holds a stable 60 frames per second, since the README states it will not work well otherwise, that you fetch releases through the OpenTaiko Hub rather than the repository, and that the licences of the particular skin and song packages you use are ones you can follow.

## FAQ

### What is OpenTaiko?

It is an open-source rhythm game engine written in C# for playing .tja chart files, described as Old TJAPlayer3-Develop-BSQ and a spiritual successor to TJAPlayer3. Its goals are multiple fun ways to play Taiko, more customization for skinning, and quality-of-life work, and it is licensed MIT.

### How do I install OpenTaiko?

From 0.6.0 onwards, the project asks you to download and manage releases through the OpenTaiko Hub at github.com/OpenTaiko/OpenTaiko-Hub. Songs, skins and other assets are separate repositories, with the soundtrack and the skins each in their own repository, and only the minimum is provided here for development purposes.

### Does OpenTaiko need a fast computer?

The README states that if your PC cannot maintain 60 frames per second stably, it will not work well with the software. The project also says use of the software is your own responsibility and that the creator will not take responsibility for problems arising from it.

### Can I modify OpenTaiko and redistribute it?

Yes, under the MIT licence you may make edits and secondary distribute, at your own responsibility. You are asked to include the License folder of the libraries used, and to follow the creators' licences for other skin and song packages, since the OpenTaiko licence does not apply to those.

### Will OpenTaiko recreate the UI of a commercial Taiko game?

No. Copying other games and commercial licences accurately is an explicit non-goal, the team is strongly against secondary distribution of skins reproducing specific commercial video games, and feature requests to recreate a commercial game's UI/UX will be denied and left without answer.

### How do I report a crash in OpenTaiko?

Include the release version and recreation steps, and attach the TJAPlayer3.log file if it is a crash. The project asks that you research before asking people, and it also asks that posts follow Japan and France copyright laws.

## Sources

- [0auBSQ/OpenTaiko on GitHub](https://github.com/0auBSQ/OpenTaiko)
- [Issues](https://github.com/0auBSQ/OpenTaiko/issues)
- [License: MIT](https://github.com/0auBSQ/OpenTaiko/blob/main/LICENSE)
- [README](https://github.com/0auBSQ/OpenTaiko/blob/main/README.md)
- [Releases](https://github.com/0auBSQ/OpenTaiko/releases)

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Hysen Labs editorial analysis, written from the project's own repository and release notes. Cite the canonical page: https://hysenlabs.com/projects/0aubsq-opentaiko