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Birth chart vs Chinese birth chart: two ways of casting a moment
A birth chart usually means the Western natal chart: the Sun, the Moon and the planets placed against the zodiac, drawn as a wheel. The Chinese chart cast from the same moment arranges twelve palaces and the stars that fall in them.
The short answer
What each one is computed from
A Western natal chart takes the date, the exact time and the place, and computes planetary longitudes, house cusps and aspects; the result is a wheel of signs and houses. The Chinese chart takes the same three inputs, converts the clock time to true solar time, and places the 紫微 series of stars into a fixed grid of twelve palaces.
The Chinese side carries no planetary positions at all: its astronomy stops at the calendar — stems, branches and solar terms. That is why neither chart can be derived from the other.
Which of the two is cast here
The Chinese one. Enter a date, an hour, a city and a gender, and the twelve-palace chart comes out in the browser, free; the paid tiers write the reading from it.
The planetary wheel is on this page as the other side of the question; it is not cast or sold on this site.
Which one you are looking for
For the planetary wheel — planets, signs, houses, aspects — that is the Western natal chart, and a practitioner of that craft.
What is cast here is the Chinese chart. The method page sets out how it is computed, and the sample page carries one chart read from the first line to the last.
All readings See a completed reading first Cast your chart first — free
Questions
Is a Chinese chart cast from the same details as a natal chart?
Yes — date, exact time and place are what both need. On this site the city matters as much as the clock, because the place fixes the true solar time.
Is the exact birth time required?
The hour is what the palaces and stars are placed by. If it is unknown, the chart can be cast without it, and the parts that depend on the hour are marked rather than guessed.
Does the Chinese chart include the planets?
Its astronomy stops at the calendar — years, months, days, hours, stems, branches and solar terms. The reading is written from the palaces and the stars in them.