X is time. Y is momentum.
NatalXY reads your birth time through two Chinese systems — Bāzì 八字 and Zǐwēi Dǒushù 紫微斗数 — both of which sit on top of a calendar that has been used to record time for over two thousand years. This page shows where each piece comes from, and marks which parts are observed, which are documented history, which are traditional interpretation, and which are our own model.
You do not need to read this to use NatalXY. It is here so that you can check us.
NatalXY does not invent a tradition. It uses two specific, well-documented systems for reading a birth time, and keeps them in the calculation layer rather than in your way.
Records the year, month, day and hour of a birth as four stem–branch pairs — eight characters in total. In use since roughly the Tang dynasty.
Divides a life into twelve houses — identity, partnership, work, resources, home and so on — and places symbolic “stars” across them. Its written record is considerably shorter than the calendar’s, and we say so.
Partly, and it is worth being precise. NatalXY uses no planets, no constellations and no zodiac signs. Its inputs are calendar coordinates: where your birth falls inside a repeating 60-step counting system that East Asian astronomers used to record time. That system is real, documented history.
What is not established is the step after that — the traditional proposition that your position in that cycle says something about your life. We inherit that proposition, we find it worth modelling, and we do not claim it has been proven. That is exactly why the product asks you to test it against events you actually lived through instead of asking you to believe it.
Ancient East Asian timekeepers watched the Sun’s path, the length of shadows, seasonal change, rain, temperature, and the behavior of living things.
Time left a visible trace.
Èrshísì Jiéqì 二十四节气 — the Twenty-Four Solar Terms divided the Sun’s annual motion into twenty-four positions used to organize seasonal knowledge and practice.
Read the UNESCO source ↗Tiāngān 天干 — Heavenly Stems move through ten positions. Dìzhī 地支 — Earthly Branches move through twelve. Together they form Gānzhī 干支, a sixty-position cycle beginning with Jiǎzǐ 甲子.
Yáng 阳 describes outward, visible movement. Yīn 阴 describes inward, hidden, restorative movement. Neither means good or bad. The Wǔxíng 五行 — Five Phases describe what transformation is doing.
One life.Five functions of change.
Light, temperature, food, location, and internal clocks affect living systems. Yet different systems respond at different times and in different ways.
Shared time does not create identical experience.
NatalXY uses birth date, local time, and place to establish a starting coordinate, then follows how longer and shorter timing layers interact.
An early rising phase: movement begins by building direction.
Everyone encounters the same broad areas of life. What differs is how each domain is structured, when it moves into the foreground, and how strongly it moves.
The same twelve domains. A different rhythm for every life.
One part of life can rise while another consolidates or restores.
Add the moments that shaped you. See where they land. Notice what rises together, what arrives later, and what contradicts the pattern.
You do not have to accept the map on belief alone.Find my starting coordinate
East Asian timekeeping, solar observation, cyclic notation, and traditional languages of change.
Available Momentum, Life Chapters, domain movement, and your current coordinate.
That Qì is a measured physical field, or that astronomy scientifically proves personal fortune.