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.
The palace at the north, the city to its left and right
Put the palace enclosure at the north end of the central avenue, facing south down its length to the city gate; govern the half of the city on the emperor’s left (east) and the half on his right (west) as two capitals.
Here the Japanese capitals follow Chang’an rather than the Kaogong ji: the palace does not stand in the middle of the city but at its north edge, so that the ruler looks south over his whole capital. From the Suzaku-mon of the palace, Suzaku-ōji runs south to the Rashōmon; the Left Capital (Sakyō) lies east of it and the Right Capital (Ukyō) west, each with its own office, its market and its state temple: Tō-ji and Sai-ji, the only temples first allowed within the city, which stood on either side of the Rashōmon.
Heian-kyō had no city wall. Only a low wall and ditch flanked the Rashōmon; the capital was defined by its grid, not by fortification. By the late tenth century the western half had largely emptied, and the essayist Yoshishige no Yasutane described its fields and abandoned houses, while the eastern half filled up and spread beyond its eastern edge toward the Kamo River.
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)
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
Lay the mats of a room so that their joints form T-junctions: no point where the corners of four mats meet, and no continuous seam running straight across the room.
Cite this page Chris Paton, “The palace at the north, the city to its left and right”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/heian-palace-north. Text, drawings and models licensed under CC BY-NC 4.0.