Take the section of the standard timber, the cai, as the module of the building: it is 15 fen high and 10 fen wide, and every member is dimensioned in fen.
1 cai = 15 fen (height) × 10 fen (width)
Rules · Cities · Proportion · Façades · Walls
Gate five, palace corner seven, city corner nine
Set the ridge of the palace gates at five zhi, the corner towers of the palace at seven, and the corner towers of the city wall at nine, a zhi being one zhang (ten feet) in height.
palace gate : palace corner : city corner = 5 : 7 : 9 zhang (≈ 11.5 : 16 : 21 m)
The rule sets the skyline of the capital by odd numbers rising outward from the ruler: the gate through which he is approached, the corners of his palace, and the corners of the city that encloses everything. The text continues that the standards descend by rank (the palace corner of the king is the city corner of a feudal lord, and the gate of the king is the city corner of a lesser noble), so that height itself declares the order of the realm.
With a Zhou foot of about 23 cm the three heights are about 11.5, 16 and 21 m. The gate halls, corner towers and gate towers of the town are built to them.
Related rules
There are eight grades of cai, from 9 × 6 cun down to 4½ × 3 cun; use the first for great halls of nine or eleven bays and the smallest for pavilions and ceiling coffers.
grades 1–8: 9×6, 8¼×5½, 7½×5, 7.2×4.8, 6.6×4.4, 6×4, 5¼×3½, 4½×3 cun
For a great hall, measure the distance between the front and back eave purlins and raise the ridge purlin above them by one third of it; for lesser halls, by about a quarter.
rise = ⅓ × depth between eave purlins (halls); ≈ ¼ (+ a small addition) for ting-tang halls
Make the central bay (mingjian) the widest and let the bays diminish toward the ends; keep the eave columns no taller than the width of their bay.
Make each column a little taller than the one nearer the centre, so that the corner columns stand highest: by 2 cun per column outward from the central bay, giving 6 cun at the corners of a seven-bay hall and 1 chi 2 cun for thirteen bays.
corner rise = (bays − 1) cun · each step outward = 2 cun
Lay out the royal city as a square of nine li on each side, with three gates in each wall and, within, nine roads running north–south and nine east–west, each wide enough for nine chariots abreast.
side = 9 li · 3 gates × 4 sides · 9 jing + 9 wei · road width = 9 gui (tracks)
Cite this page Chris Paton, “Gate five, palace corner seven, city corner nine”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/kaogongji-corner-heights. Text, drawings and models licensed under CC BY-NC 4.0.