Gengou Lib

Name: Gengou Lib
Rating: 3.6 (40 reviews)
Author: Masayuki Akamatsu

By: Masayuki Akamatsu App

Japanese-Christian Years

Overview

Version:

3.0.1

Last updated: 2026-07-04

Ranking

#239,246 ▼ 771

Overall

Features & Capabilities

"Gengou Lib." is a quick reference of the Japanese era system. This application has functions as below.

Era and Year Search
Period picker
Era picker
Christian era year picker
Japanese era year picker
Show this year button
Texts can be shown in Japanese or English independently of the default language setting.
Application badge can show this year number in the Japanese era or the Christian era.

The Japanese era system identifies a year by the combination of the era name (Gengou or Nengou) and the year number within the era. For example, A.D. 2001 is Heisei 13. Please note that two Gengou schemes were used in Parallel from 1331 to 1392 during Nanboku-chō period.

This application would be very useful if you are working with the governments, municipal offices and/or certain companies in Japan.

User Growth & Download Statistics

App

By:

Masayuki Akamatsu

Rating:

3.60

(40)

Version:

3.0.1 Last updated: 2026-07-04

Version code:

887831674

Creation date:

2019-02-12

Compatible devices:

Size:

6.28MB

URLs:

Website ,Privacy policy

Full description:

Source:

Apple Apps Store

Data ingested on:

2026-07-23

Compare stats and ranking:

Ranking

# 239,246 ▼ 771

For Developers

Monetize with App Pass Boost with Extension Booster

Contact the developer

Chrome-Stats does not own this Apple app. Please use these information below to contact the Apple app developer.

Developed by:

Masayuki Akamatsu

Apple Apps Store

https://apps.apple.com/jp/app/gengou-lib/id284830543?l=en-US

Website:

http://akamatsu.org/iphone/

User Reviews

Users repeatedly praise Gengou Lib as a free, clean, and easy-to-use tool for converting between Gregorian dates and Japanese era years. Its core feature—two synced wheels—lets users quickly look up dates and is handy for real-life tasks in Japan (banking, housing) and for pop-culture references. Most see it as a lightweight reference that does what it promises, valuing simplicity and zero cost, though some wish for more features.

Pros

Efficient Gregorian to Japanese era date conversion with synced wheels that keep both calendars in sync.
Free to use with no cost.
Clean, simple UI that is quick to use as a reference tool.
Practical utility for real-life tasks in Japan (banking, renting) and for living abroad.
Helpful for quick lookups and J-culture references.

Cons

Recent reviews

My wife and are always trying to figure out dates in Emperor years, so this is helpful. Don't think that the current emperor is going to make it until the year 2100 though.

by Fu*****, 2010-02-02

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!