Hifuu OS is an immersive hacking simulator based on the Touhou Project. Play as Renko Usami, a female university student who lives in Kyoto in the near-future scientific century. Learn and use authentic Unix terminal commands to hack into the Great Hakurei Barrier. Explore the cyber world of Gensokyo full of stories and secrets, join the lunatic elite hacker team EagleSec, and use advanced hacking skills to freely influence and change the lives of the residents of Gensokyo. It all started with the mysterious coma of Renko's best friend and a member of the Hifuu Club, Maribel Hearn...

Fully Immersive

Hifuu OS boots your computer into a vintage terminal-based machine from the 1980s. The purely text-based user interface brings you right back to the wild west of the early days of the Internet, where security loopholes floated all over the place. Communicate with in-game characters and progress the game via the built-in email.

Engaging Stories

Uncover the truth behind Maribel Hearn's mysterious coma as you search through private files from computers used by Gensokyo's residents and organisations. Accept the invitation from the lunatic elite hacker team EagleSec, alter the cybernetic world within the border as you see fit, and become a Gensokyo cyber outlaw.

Real Experience

Take the Kyoto University Computer Security 101 course as Renko, and learn the knowledge of using Unix commands to navigate and manage file systems applicable both in the game and in the real world. Familiarise yourself with a series of computer security concepts and practices while hacking into weakly-protected systems.