Last updated: October 9, 2026
These terms govern your use of KOURAKU ("the App").
The App is an educational tool for learning navigation, celestial navigation, and positioning. Its content is simplified for educational purposes; for professional, academic, or operational use, please consult reliable textbooks, literature, and observational data.
All rights to the source code, design, text, and images of the App belong to Fuji Bit Inc. Unauthorized reproduction or redistribution is prohibited.
The simulations and information in the App are simplified models for educational purposes and are not intended for actual navigation, positioning, voyage safety decisions, the operation of vessels or aircraft, or disaster prevention. The developer is not liable for any damages arising from use of the App's information.
The App is provided free of charge. There are no in-app purchases (IAP), subscriptions, or paid unlocks. The App shows banner ads from the Pangle ad service. For how ad-related information is handled, see the Privacy Policy and How We Handle Personal Data. Where ads appear, the accuracy and reliability of their content is the responsibility of the advertiser.
These terms may change without notice.
These terms are governed by the laws of Japan.