The state building manual of the Northern Song, compiled by Li Jie of the Directorate of Buildings. Thirty-four chapters of terms, methods, labour and material quotas, and drawings, all founded on one principle: every timber building is measured in cai, the standard section of timber, and its fifteenth part, the fen.
Li Jie (d. 1110) was an official of the Directorate of Buildings at the Song capital Kaifeng. An earlier manual had been judged too loose to control costs, and in 1097 he was ordered to prepare a new one. He consulted the craftsmen themselves, collected their terms and working rules, and completed the book in 1100; it was printed by imperial order in 1103. Its purpose was administrative (to let officials check estimates and prevent waste), but to do that it had to write down, with unprecedented precision, how Chinese buildings were actually designed and made.
The heart of the system is the module. “All building is based on the cai”, the section of a standard timber, fifteen units (fen) high and ten wide. There are eight grades of cai, from 9 × 6 cun for the largest halls to 4½ × 3 cun for small pavilions and ceiling coffers, and a builder first chooses the grade that suits the rank and size of the building. Every member (the height of a beam, the length of a bracket arm, the projection of the eaves, the diameter of a column) is then given in fen. A small spacer of 6 fen, the zhi, completes the vocabulary: a cai plus a zhi, 21 fen, is a “full timber” (zucai), the vertical step of every tier of brackets.
The greater carpentry chapters (juan 4–5) describe the bracket sets (puzuo) tier by tier, with their blocks (dou), arms (gong) and slanting levers (ang); columns, beams, rafters and eaves; and the method of “raising and depressing” (jǔzhé) by which the curved section of the roof is drawn. The lesser carpentry chapters cover doors, windows, screens, ceilings and sutra cabinets; others deal with stone, brick, tile, plaster, colour painting and kilns. Half of the book is quotas (how many working days each operation takes, how much material each member needs), and the final six chapters are drawings of plans, sections, bracket sets and painted patterns.
The book was reprinted in the Southern Song and then almost forgotten. In 1919 the scholar-official Zhu Qiqian found a manuscript copy in Nanjing and published it; the Society for Research in Chinese Architecture which he founded set out to understand it by measuring surviving Song and Liao buildings. Liang Sicheng and Lin Huiyin spent the 1930s on that search, which led to their discovery of the Tang East Hall of Foguang Si in 1937, and Liang’s annotated edition, completed over decades, became the foundation of the modern study of Chinese architecture.
The book, part by part
I Juan 1–2: Explanation of terms
The names of building parts gathered from the classics and from craftsmen’s usage, with their variant forms: many parts had half a dozen names.
II Juan 3: Moats, fortifications and stonework
Earthworks and rammed earth; stone platforms, column bases, balustrades and steps.
III Juan 4: Greater carpentry (cai and bracket sets)
The eight grades of cai; the fen and the zhi; the parts of the bracket set and their dimensions in fen; sets of four to eight puzuo.
Rules: Everything is measured in cai and fen · Choose the grade of cai by the rank of the building · A full timber is a cai and a zhi: 21 fen · The bracket set steps out 30 fen a tier · The ang: reach further without climbing
IV Juan 5: Greater carpentry (beams, columns, rafters, eaves and roof)
Beams and their sizes; columns, with the rising of the corners (shengqi) and the inward lean (cejiao); rafters and eaves; the roof raised by a third and depressed by the jǔzhé method.
Rules: Raise the ridge by a third of the depth · Depress each purlin: 1/10, 1/20, 1/40… · Shengqi: raise the corner columns · Cejiao: lean the columns inward · Round off the ends: juansha · Eaves in proportion to the rafters · Let the eaves grow out at the corners · The central bay is the widest; columns no taller than a bay is wide
V Juan 6–12: Lesser carpentry, carving, turning, sawing, bamboo
Doors, lattice windows, partitions, ceilings and caissons, sutra cases; carving and turned work; bamboo matting.
VI Juan 13–15: Tiles, plaster, painting, brick and kilns
Tiling and ridge building, including the ornaments at the ridge ends; plastering; the five systems of colour painting; brickwork; firing tiles and glazes.
VII Juan 16–28: Labour and materials
Quotas of working days and materials for every operation: the book’s administrative purpose.
VIII Juan 29–34: Drawings
Plans and sections of halls of each type, bracket sets, carpentry details and painted decoration.
Rules: The raised-beam frame: purlins at any height · The hip-and-gable: nine ridges