Gengou Lib 4+

This app is just to convert years on the Gregorian calendar to/from those in the Japanese empirical calendar. This can be done simply with one's brain or a calculator, however. It does what it's supposed to do, but really nothing more; if you're like me and you have plenty of apps littering your home screens, this probably won't be one app you'll keep. At least it was free.

As other reviewers have noted, this app lets you convert between gregorian and japanese era calendars. It does this by presenting two spinning wheels (one with the western year, the other with the japanese year) which are locked to one another - you can spin either one and the other will turn to match, letting you look up the corresponding date. Of course, you *could* do this in your head, especially for the most current era (heisei) since you always know what the most recent year of the era is, but once you start getting into past eras, it becomes increasingly difficult unless you have the exact years of the emperor's death and the length of their reign memorised, something which most Japanese, especially young people, do not. For this reason, most Japanese day planners come with a small conversion chart in the back for reference. If you live in Japan and have such a chart you probably won't need this application but if not, and you find yourself needing to convert between the two calendar systems, it can be quite handy. At any rate, it's free, so you can't go wrong!

Svaiyre left something out in the review. Yes, you can do what this app does by yourself using a calculator or your brain... IF you have an intimate knowledge of Japanese history and know the dates when the emperors died by heart. For the rest of us, this is an invaluable tool with many uses. It saved me 4 times in the last 3 weeks, especially while trying to sign up for a bank account and renting a mansion.

Now if you'll excuse me, I have a heisei 19 mansion to move into