# Daimyo Clock — Traditional Japanese clock

> Recreation of a 17th-century Japanese mechanical clock showing traditional time divisions. (iPhone/iPad app by Douglas Hildum.)

- Source: https://appshunter.io/ios/app/daimyo-clock/id1268135788 (this page in markdown: same URL + `.md`)
- Developer: [Douglas Hildum](https://appshunter.io/developer/1268135787)
- Category: Education, Utilities
- Price: Free
- Rating: 4.00/5 from 1 App Store ratings · 1 written reviews indexed
- Age rating: 4+
- Requires: iOS 16.0 · 1 MB
- Languages: American English, Japanese
- Released: 2017-11-12
- Data updated: 2026-06-01
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/daimyo-clock/id1268135788/reviews.md

## What is Daimyo Clock?

Daimyo clock is a recreation of a mechanical clock developed in the seventeen century based on western clocks but modified to show traditional Japanese time.
Traditional Japanese time divides the day and night into six equal periods from dawn to dusk and dusk to dawn respectively. Over the course of a year as the daylight and nighttime periods lengthen and shorten, the length of these six day or night periods change. Unlike Western clocks which are regulated by a single pendulum and run at a constant speed day or night, Japanese clocks incorporated two pendulums, and switched between them at dawn and dusk. Adjustment for the changing daylight and nighttime hours was accomplished by adjusting the effective length of the pendulums, normally done every two weeks, or twenty-six times a year. This kept the time shown on the clock reasonably close to the correct time, provided that the clock had been set correctly initially.
This modern implementation is much more accurate and precise than the original clocks. In this implementation, the biweekly adjustments of the mechanical clock are made continuously, thus the day or night period length are always correct. Noon on the clock will, if location services are enabled, occur when the sun is at the zenith, or solar noon. Day start and end correspond to the beginning or end of twilight, and are calculated accounting for the refraction of the Earth's atmosphere.
There are three situations where the clock my not show the local time in the Japanese manner:
1. If location services are off, Daimyo Clock will show the time for Tokyo, Japan. 東京 will be displayed on the clock face in this case.
2. While the application is obtaining an updated location after launch or returning to foreground.
3. Near the North or South poles the sun may either be above the horizon or below it for the entire day (24 hour period). In this case, the Japanese definition of time no longer applies, so the clock face will be shown without a clock hand.

## Key features

- Traditional Japanese timekeeping
- Day/night divided into six equal periods
- Seasonal daylight adjustments
- Accurate solar noon calculation
- Location-based time display
- Twilight start/end calculation

## Recent user reviews (1 of 1)

All indexed reviews: https://appshunter.io/ios/app/daimyo-clock/id1268135788/reviews.md

### 4/5 — Interesting, but more would be fun

*2020-04-05*

It would be nice if it translated the Japanese symbols and told you which division and zodiac sign it is showing.   As in, third division of the rat, or whatever.

## Frequently asked questions about Daimyo Clock

### What is Daimyo Clock?

Daimyo Clock is a modern implementation of a 17th-century mechanical clock that displays time according to traditional Japanese divisions. It divides the day and night into six equal periods, adjusting their length based on the season.

### How does Daimyo Clock handle traditional Japanese time?

It recreates the system where day and night are each divided into six equal periods. The length of these periods changes throughout the year as daylight hours vary, a concept different from standard Western timekeeping.

### Does Daimyo Clock require location services?

Yes, for the most accurate local time display. If location services are off, it defaults to showing the time for Tokyo, Japan, indicated by '東京' on the clock face.

### How accurate is Daimyo Clock compared to original clocks?

This modern implementation is significantly more accurate. Unlike original mechanical clocks that required manual adjustments, Daimyo Clock continuously adjusts for changing daylight and nighttime periods.

### What happens near the North or South poles?

In regions with 24-hour daylight or darkness, the traditional Japanese definition of time no longer applies. In these situations, the Daimyo Clock face will be displayed without a clock hand.

### What is the age rating for Daimyo Clock?

Daimyo Clock is rated '4+' by the App Store, making it suitable for a wide range of users interested in its educational and historical content.

### When was Daimyo Clock last updated?

The app was last updated on December 6, 2023, with version 1.2.0. This indicates ongoing support and potential for future improvements.

### Does Daimyo Clock have ads?

No, Daimyo Clock is ad-free. Users can enjoy the traditional timekeeping experience without interruptions from advertisements.

## Version history (last 3 releases)

### 1.2.0 — 2023-12-06

Dark mode support and performance improvements

### 1.1.0 — 2022-03-04

Updated for iOS 15

### 1.0.0 — 2017-11-12

This app has been updated by Apple to display the Apple Watch app icon.

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## Related topics

[daimyo clock](https://appshunter.io/ios/topics/daimyo-clock)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-01.*