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 · Plans · Proportion
Roads of nine, seven and five tracks
Make the avenues within the city nine chariot-tracks wide, the ring road that runs inside the wall seven tracks, and the roads in the country outside the gates five.
avenue (jing tu) 9 gui · ring road (huan tu) 7 gui · country road (ye tu) 5 gui · 1 gui = 8 chi
The track (gui) is the gauge of a chariot, which Han commentators give as eight Zhou feet. The three widths make a hierarchy of movement: the widest roads are those that cross the city from gate to gate, the ring road inside the wall is for troops and carts going round, and the roads outside are narrower still. The usual reading of the text takes each of the city’s nine roads in each direction as one of three parallel carriageways through each gate; the Book of Rites adds that men keep to the right, women to the left and carriages to the middle.
In the town each avenue is drawn as three lanes of three tracks, about 5.5 m each, so that together they make the nine; the ring road is 13 m and the roads beyond the gates 9 m. The road widths are true to the text; the distances between them are reduced about four times.
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.
Give a hall an odd number of bays across the front (three, five, seven, nine or eleven) so that the central axis passes through a bay and a doorway, never through a column.
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, “Roads of nine, seven and five tracks”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/kaogongji-road-grades. Text, drawings and models licensed under CC BY-NC 4.0.