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Robert Jordan edited this page Jun 15, 2023 · 26 revisions

CatSystem 1 + 2 Documentation Wiki

CatSystem2 Demo Title

TriggersTools.CatSystem2 is a library designed to make working with CatSystem 2 file formats quick and easy. This wiki, however, is aimed at information on the CatSystem 1 + 2 engines in general like: File Specifications, undocumented functionality, localization, patching, and so on.

CatSystem 1 icon, featuring a cat and the text CatSystem CatSystem 1, (abbreviated Cs with no '1'), is a Japanese visual novel engine for Windows.
It's first and last VN releases appeared in 1999 through 2002. It was developed by Usagi Club, who later formed into Cat Works Team. The engine is used for other semi-VN gameplay types, like common drop down puzzle games. The final releases on this engine were a joint effort with Windmill.

CatSystem 2 icon, featuring Manju and the text CS2 CatSystem 2, (abbreviated Cs2), is a Japanese visual novel game engine for Windows (and other systems: PSVita, Android, Switch).
Its first VN release appeared in 2004. It is developed by Windmill (ARES inc.), who presumably had fully absorbed Cat Works Team by this time.
CatSystem 2's mascot character is Manju: Manju :3 who appears on the Cs2 program icon.


🔦 The Wiki Home and sidebar Table of Contents is outdated
Many new and completed Wiki pages still have no links leading to them.
Use the Pages List in the sidebar for a complete look at the Wiki and latest information.


Wiki main pages

  • General Info - Important information to known before working with CatSystem 2
  • File Formats - File specifications and decryption
  • Encryption Methods - In-depth explanation on CatSystem 2 encryption
  • Decompiling - Decompiling .anm, .cst, and .fes scripts into compilable text files
  • Localization - Hurdles when translating Cs2 games
  • Debug Mode - Activating and using in-game Cs2 debugging tools
  • Shift JIS - Notes on the Japanese character encoding used by CatSystem 1 + 2
  • Tools and Programs - Comprehensive list of known tools for CatSystem 1 + 2, and individual pages documenting them
  • Engine Transplants - Ongoing study of modifying game internals with newer Cs2 engine versions, for localization and compatibility

Games tested against

🚧 This list needs updating, at least 20 different samples of CatSystem 1 + 2 games and trials have been inspected since

This is a list of all games that have been involved in testing of the CatSystem 2 library, which helps improve knowledge of the file formats and other functionality.

This list is in dire need of expansion outside of Grisaia games and the Cs2 Toolset.

Helpful resources

Useful projects

Japanese links 🇯🇵

If you cannot read Japanese, then it is recommended to view these links with Google Chrome. You may also use Google Translate's webpage translation service, but Google Chrome is faster and has the ability to turn on and off translations. It's important to note that when viewing the translated CatSystem 2 manual, whitespace will not always be correct. You should turn off and on translations to compare how the whitespace should actually be when reading the manual's codeblocks.

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