Utilities
Gengo Seireki - Japanese Era & Zodiac Converter
Western years, Japanese eras, zodiac, emperors and prime ministers in one timeline.
What makes this app great, in a nutshell
Gengo Seireki is an iPhone app that puts Western years, Japanese era names, the zodiac, emperors and prime ministers side by side in one timeline, so you can look up any period at a glance. It covers every era from Taika (645) to Reiwa, including the eras of the Northern and Southern Courts. Tap a year to see how many years ago it was, or tap two years to see the years between them and how many era changes occurred. Register family members to see milestone years such as Shichi-Go-San, yakudoshi and kanreki on the timeline, along with major battles and events from the Genpei War to World War II.
Features
- A timeline showing Western year, era name, zodiac, emperor and prime minister in one row (up to 5 custom columns), including Northern and Southern Court eras
- Tap a year to see how long ago it was; tap two years to see the span and number of era changes
- Twelve zodiac animals and the 60-year sexagenary cycle (optional animal icons)
- Major battles and events from the Genpei War to WWII, with family crests and flags
- Favorites, history, and per-year notes (paid version)
- Filter by period, era or zodiac; adjust text size, furigana and dark mode
Made for moments like these
I want the Western year for an era date like Showa 50
Western years and era names sit on the same row, so you can read the year without converting.
→ Era/Western year timeline
I want the zodiac sign of a year or how many years ago it was
Tap a year to see how many years ago it was. The twelve animals and the sexagenary cycle are shown too.
→ Tap a year / zodiac
I want to know how far apart two years are
Tap two years to see the number of years between them and how many times the era changed.
→ Difference between two years
I want to know the emperor or prime minister of a given year
Emperors and prime ministers appear in the same timeline. You can rearrange up to five columns.
→ Customizable columns
I want to check the Shichi-Go-San or yakudoshi years for my family
Register a family member to show their Shichi-Go-San and yakudoshi (when gender is set) years on the timeline.
→ Person registration
I want to know the years for longevity celebrations
See the years of longevity celebrations, from kanreki (60) to hyakuju (100), for each registered person.
→ Person registration
I want to follow Japanese history on a timeline
Major battles and events from the Genpei War to World War II are shown with family crests and flags.
→ Battles and events
I want to go back to eras before the Edo period
Look up any era from Taika (645) to Reiwa, including the Northern and Southern Courts.
→ Years before Ansei (paid)
I want to keep the years I look up often
Save them to favorites and history. Long-press a timeline row to copy it and paste it into another app.
→ Favorites, history and copy
Frequently asked questions
Which years does it cover?
Every Japanese era from Taika (645) to Reiwa. The free version shows 1854 onward; years up to 1853 (Ansei and earlier) are a paid feature that you can use for 5 minutes after watching a video ad.
Does it show the eras of the Northern and Southern Courts?
Yes. Eras of both the Northern and Southern Courts are shown.
How much can I do for free?
The timeline, year-difference calculation, zodiac and battles/events are free (with ads). The paid version (monthly, yearly or lifetime) adds years before Ansei, 50 history and 200 favorite entries (3 each for free), hiding the era column, yearly notes and up to 10 registered people (1 for free). Watching a video ad lifts these limits for 5 minutes.
Are the people and notes I register sent anywhere?
No. Registered people and notes are stored on your device and never sent externally. The free version uses the network to show ads.
Can I use it on iPad or Mac?
It is an iPhone app (iOS 18.0 or later).