BaZi Atlas

As someone building in the astrology space myself, the 'private by design' choice really stands out - birth data is about as personal as it gets, and computing everything client-side with lunar-javascript means there is genuinely nothing to breach. I also respect the methodology page with a public corrections log: BaZi has so many competing conventions (true solar time vs standard time, early/late zi hour handling) that documenting every rule is the only way to be credible. One question: does the calculator show which convention choices were applied for a given chart, e.g. which zi-hour rule or time correction was used? For a research tool, exposing that per-chart would be genuinely valuable.

Nice to see lunar-javascript doing everything client-side. We use the same library for a Four Pillars page, and solar-term boundaries were the part we had to test hardest. Since you ask for the birth place: do you also apply historical daylight saving time? China used DST in 1986-1991 and Japan in 1948-1951, so a summer 1988 birth at 1:30 on the clock lands in a different hour pillar unless it is shifted back an hour. A short note on each chart saying which corrections were applied (DST, true solar time from longitude) would make cross-checking against other apps much easier.

I built BaZi Atlas because every BaZi calculator I tried was either a black box, paywalled, or sloppy with the rules. As a developer, I wanted an engine where every computation is documented and correctable - so I open-sourced it (MIT) and keep a public corrections log on the methodology page. Everything runs client-side: your birth data never leaves your browser. The English and Chinese editions share the same engine, and the tool library (ten gods, compatibility, luck pillars, hexagrams index, etc.) grew out of questions learners kept asking. Happy to answer anything about the engine, the rules, or the roadmap. If you spot a calculation issue, the corrections page is the fastest way to get it fixed.