Birthday Color Cafein

What this site does

Type your birthday and you get a color, a season, a piece of poetry, and a few related readings — a guardian creature from Shanhaijing, a Five Elements profile, a fragrance pairing, a chemistry match, a daily fortune. None of these are predictions. They are traditional cultural lenses assembled into a small toy you can play with in five seconds.

Why it exists

The viral Japanese site birthday-color.cafein.jp assigns one color to every day of the year. It is beautiful, but its 366-row mapping is a compilation work protected by copyright, and it is rooted in 和色 — Japanese palette names like 桜色 and 浅葱. I wanted the same daily-color experience but built from the Chinese tradition I grew up with: the inks of Song dynasty paintings, the dyes of Tang silk, the porcelain glazes of Jingdezhen. So I rebuilt the whole thing from scratch.

How the algorithm works

There is no copy of any existing chart on this site. Each date is assigned a color by a deterministic hash:

hash = m·31 + d·7 + m·d + 3·d²

The hash picks an index inside the seasonal pool of sixteen Chinese traditional colors. Spring runs from 立春 to 立夏, summer to 立秋, autumn to 立冬, then winter — the solar terms of the Chinese calendar, not the Western months. The full palette is open in palette.js in the page source. You can read every line.

What you won't find here

No personalized predictions. Nothing on this site claims to know your future, your medical condition, your relationship outcome, or your finances. Everything is a creative interpretation of date-based traditions, written by a human who finds them interesting.

No collected personal data. Your birthday never leaves your browser. The site has no backend — every calculation runs on your device. The only data we receive is anonymous Google Analytics traffic stats.

How this is funded

This site is free to use. There are no ads, no subscriptions, and we never sell your data. The project is supported entirely by an optional one-time purchase — the paid Bazi personality report (Core portrait $8.99 or Full profile $12.99, in US dollars). Buying it is completely optional; every other tool on the site stays free. Payments are handled securely by a third-party payment provider, and we never see or store your card details.

Who I am

My name is Ele Sun. I’m a designer-developer based in East Asia, and a mom to two little girls. I’m not a fortune-teller, an astrologer, a feng shui consultant, or a brand. I made this because I genuinely find it interesting, and I’d love for people to bring a little more color into their everyday lives — starting from their own birthday. If you spot a mistake, see something culturally inaccurate, or want to share a beautiful Chinese color name I missed, please reach out via the Contact page.

At a glance

• Founded
  2026
• Run by
  One independent designer
• Based on
  64 traditional Chinese colors
• Languages
  English · 中文 · 日本語 · Русский
• Source
  Static HTML / JS, no backend
• License
  MIT — code is open

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