Sources & Licenses
This service's readings and calculations draw on the following external data and libraries.
Name Numerology (Stroke Counts): KANJIDIC2
Stroke counts for the new-form glyphs of the jōyō and jinmeiyō kanji (about 3,000 characters) are generated from the stroke_count field of KANJIDIC2, published by the Electronic Dictionary Research and Development Group (EDRDG).
EDRDG licence: EDRDG Licence
License: CC BY-SA 4.0
To decide which characters count as jōyō or jinmeiyō kanji, we use the kJoyoKanji / kJinmeiyoKanji fields of the Unicode Han Database (Unihan), published by the Unicode Consortium. (The stroke counts themselves still come from KANJIDIC2 — we do not use Unihan's kTotalStrokes, which counts strokes the Chinese way.)
License: Unicode License
Solar Term Accuracy Check: NAOJ "Koyomi Yōkō"
We verify the accuracy of our solar term (setsuiri) calculations, used by the Four Pillars and Nine Star Ki systems, against the published values from the National Astronomical Observatory of Japan's "Koyomi Yōkō". This is a reference for checking correctness, not a data source.
Ephemeris Calculations: astronomy-engine
Positions of the sun and moon and other ephemeris calculations needed for Western astrology and solar terms use astronomy-engine.
Positions of the Sun and planets rest on truncated VSOP87 series; the Moon is computed with the Nautical Almanac Office’s Improved Lunar Ephemeris (1954) lineage. The design target is agreement with NOVAS C 3.1 to within one arcminute. ELP is not used for the Moon.
License: MIT License
Sources and scholarly basis for each method
The classics, modern origins, scholarship and school differences for every method are on a separate page.
QR Code Generation: qrcode-generator
The invitation-link QR code feature uses qrcode-generator.
License: MIT License