This app is only useful if you're in Japan and read Japanese.
Good app for tracking vaccinations with multiple children (which can be confusing). I like the reminder function and the fact that I can see my kids' vaccination statuses without digging out my boshi-techo.
I do, however, wish that some customization was possible, such as adding vaccinations not standard to Japan (like Hep A).
Useless
First, this app is designed in accordance with the standard vaccine schedule in Japan. You cannot customize at all. No translation.
You live in Japan? That sounds good. The app give you information of vaccines available for your children based on age, including frequency. You have to read them very carefully, and make schedule by yourself. The app will give you reminders. That's all.
So, you will find that you have already much better apps than this: standard calendar and task scheduler. The only things you have to do are to check web and then to add schedule, instead of installing this app. It's easy.