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.
An odd number of bays
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.
Li Jie lists halls of three, five, seven, nine and eleven bays when he matches the grades of cai to buildings; the rule was so universal that it hardly needed stating. The axis of a Chinese building is a line of movement, through gates, courts and doors toward the principal seat, and a column standing on it would block it. The Hall of Supreme Harmony has eleven bays; the Hōryū-ji kondō in Japan, whose upper storey has four, is a famous exception.
Related rules
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)
With the palace at the centre facing south, place the ancestral temple on its left (east) and the altar of soil and grain on its right (west); put the court in front and the market behind, each one fu (a hundred paces) square.
Find true north and south with a plumb-lined post and the shadows of sunrise and sunset, checked by the pole star; then turn the principal hall of every compound to face south.
Set out the posts of a house on a square grid of one ken (six shaku, about 1.82 m) and size rooms, doors, screens and mats to fit the grid.
1 ken = 6 shaku ≈ 1.82 m · 1 tsubo = 1 ken² ≈ 3.3 m² = 2 mats
In the Kyoto system (kyō-ma) fix the mat (6.3 × 3.15 shaku, about 1.91 × 0.955 m) and set the posts outside it; in the Edo system (edo-ma) fix the post grid at 6 shaku and cut the mats to fit between the posts, making them smaller.
kyō-ma ≈ 191 × 95.5 cm · chūkyō-ma ≈ 182 × 91 cm · edo-ma ≈ 176 × 88 cm
Cite this page Chris Paton, “An odd number of bays”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/odd-bays. Text, drawings and models licensed under CC BY-NC 4.0.