Tử Vi chart

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What is Tử Vi Đẩu Số and how is a chart cast?

Tử Vi Đẩu Số is a classical Chinese astrological system, thought to have been formalized in the Song dynasty (10th-13th century, associated with Trần Đoàn) and transmitted to Vietnam through centuries of cultural exchange. It differs fundamentally from Western astrology (which tracks real planetary positions): Tử Vi uses a set of 14 symbolic "main stars" plus dozens of "minor stars", placed into 12 fixed "palaces" (Self, Parents, Fortune, Property, Career, Servants, Travel, Health, Wealth, Children, Spouse, Siblings) according to positions derived from your lunar birth hour/day/month/year.

To cast a chart, your solar birth date is first converted to the lunar date and hour-Branch (Tý hour, Sửu hour...), from which the Self palace and Body palace are located (via the fixed "start from Dần" rule in classical texts), then the 14 main stars (the Tử Vi star group and the Thiên Phủ star group, each placed by its own separate rule) and other minor stars are placed into their corresponding palaces. This is a fixed, rule-based procedure, not free interpretation, so any correctly cast chart for the same birth hour/day/month/year will come out identical.

The Four Transformations (Hóa Lộc, Hóa Quyền, Hóa Khoa, Hóa Kỵ) are an additional layer tied to the birth year's Heavenly Stem, giving four specific stars in the chart extra positive/negative significance. Many modern Tử Vi schools weigh this layer heavily for more detailed readings beyond the main stars' base positions.

Interpreting a Tử Vi chart, what each star means in each palace and how stars interact, is specialized work that varies a lot by school and by the reader's experience. This tool only automates the star-placement step (the fixed, objective part); the accompanying interpretation notes are general cultural reference and don't replace a detailed reading from an experienced practitioner if you want in-depth analysis.

The 12 palaces are laid out on the chart in the traditional "địa bàn" (earthly grid) arrangement: a fixed 4x4 grid where each of the 12 Earthly Branches occupies a set position, running counter-clockwise starting from Dần in the upper area. This spatial layout is itself meaningful within the tradition (it mirrors the compass-direction associations of each Branch), which is why this tool preserves the grid shape rather than flattening it into a simple list.

Among the 12 palaces, the Self palace (Mệnh) and its "opposite" palace, the Travel palace (Thiên Di, directly across the grid), are traditionally read together, the Self palace describing one's inherent nature and the Travel palace describing how one behaves and is perceived outside the home. Similarly, the Career palace (Quan Lộc) and Wealth palace (Tài Bạch) are often read as a pair for professional and financial questions, since both connect back to the Self palace through fixed triangular relationships in the grid.

The Body palace (Thân) is a special case: unlike the other 11 palaces, it does not get its own separate position, it always coincides with one of the 12 existing palaces (most often the Self, Career, Wealth, Travel, Marriage, or Fortune palace, depending on birth hour and month), and that palace is considered to carry extra weight for how one's destiny plays out over the second half of life, complementing the Self palace's description of innate character.