# Gengou Lib

> Japanese-Christian Years

Canonical page: [https://chrome-stats.com/d/id284830543](https://chrome-stats.com/d/id284830543)

## Overview

- **ID:** `id284830543`
- **Platform:** Apple
- **Type:** Apple app
- **Status:** Available
- **Publisher:** Masayuki Akamatsu
- **Category:** Productivity
- **Rating:** 2.50 / 5 (2 ratings)
- **Version:** 3.0.1
- **Last updated:** 2026-07-04
- **First published:** 2019-02-12
- **Size:** 6.28 MB
- **Data as of:** 2026-09-23
- **Store listing:** [Apple App Store](https://apps.apple.com/us/app/gengou-lib/id284830543)
- **Website:** [http://akamatsu.org/iphone/](http://akamatsu.org/iphone/)
- **Privacy policy:** [http://akamatsu.org/app/privacypolicy.txt](http://akamatsu.org/app/privacypolicy.txt)

## Description

"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.

## Rankings

- #800,608 — Overall

## Review summary

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.

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Source: [Chrome-Stats](https://chrome-stats.com/d/id284830543)