README.en.md

Wadokei

Japanese

Wadokei is a web application that recreates the traditional Edo-period Japanese temporal hour system (unequal hours) in modern browsers. It continuously displays time based on the current date/time, the 24 solar terms, sunrise, and sunset.

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🌟 Features

• Unequal-hour time system simulation Daytime and nighttime hour lengths are calculated dynamically by season.

• 24 Solar Terms display Shows the current solar term together with sunrise/sunset-related information.

• Pure frontend implementation Built with HTML / CSS / JavaScript only. No backend required.

Twilight correction based on Kansei calendar interpretation

Historical Wadokei practice often treated day/night boundaries not as exact sunrise/sunset, but with twilight transitions around them.

Wadokei includes corrections inspired by historical Japanese calendar descriptions to better approximate traditional temporal-hour behavior.

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🚀 Demo

GitHub Pages: https://tomneko.github.io/Wadokei/

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🛠 Tech Stack

• JavaScript (ES6)
• SunCalc 1.9.0
  • Used for sunrise/sunset and solar position calculations
• Custom astronomical correction logic
  • Date normalization (fixed to local 00:00)
  • Unequal-hour duration calculation
  • True solar noon derivation

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📁 Directory Structure

Wadokei/
  index.html
  docs/
    open-source-licenses.md
  core/
    wadokei.js
    config-loader.js
    consts-loader.js
  plugins/
    plugin.drawBackplane.js
    plugin.drawHand.js
    plugin.drawHand.yaesakura.js
  utils/
    datetime.js
    taiyou.js
  domain/
    24terms.js
  config/
    config.json
    consts.json

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🔧 Local Usage

1. Clone this repository.
2. Open index.html in a browser.

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📜 License

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🙏 Acknowledgements

• SunCalc