A Simple Calendar by RYOTA is a user-friendly app designed for Android devices. It is a lifestyle app that helps users keep track of important dates and events. One of its unique features is its ability to display public holidays in Japan. With just a few taps, users can see upcoming holidays and plan their schedules accordingly.

The app has a menu button that allows users to switch between a one-month display and a 12-month display. Users can also use the right-and-left button to navigate through the months in the one-month display. In the 12-month display, users can view up to 10 years of income tax data. The app's simple interface and intuitive design make it easy to use for people of all ages.

Overall, A Simple Calendar is a great app for anyone who wants to keep track of their schedule and stay on top of important dates and events. It is free to download and use, and it is a must-have for anyone living in Japan.