Replacement chart

Meaning

The replacement chart, 替卦 tìguà, Ti Gua, is the second chart that many schools read for a home whose facing lies close to the edge of its mountain: within 3° in Ulune. A facing there shares in the mountain beside it, and the classics answer with a chart cast a little differently. When the mountain and water stars are cast, the number going to the centre is replaced by the replacement star of the mountain that decides its flight, and the flight keeps its direction.

Each mountain has its replacement star, from a classical verse the Xuan Kong schools hand down, which opens 子癸甲申，貪狼一路行: Zi, Gui, Jia and Shen go all the way with Tan Lang, the 1. The verse names five stars only, the 1, 2, 6, 7 and 9, by their Dipper names. When the replacement star is the number already going to the centre, nothing changes; otherwise the whole chart flies from another number, and its formations can change too.

Schools differ here, and Ulune says so. Many read the replacement chart near an edge, others keep the main chart; Ulune shows both. A 5 going to the centre keeps its number in Ulune’s replacement chart, while some schools give it the replacement star of the home’s own mountain; and the 3° threshold is the common one, though some use 4.5° or other values.

In practice

• In the Home lens: when the facing is within 3° of its mountain’s edge, the replacement chart is shown beside the main one, with the note that many schools read it there and others read the main chart.
• On the line: within 1.5° the facing is on a void line, which many schools read with care; the Home lens suggests taking the facing again, since a degree or two decides it.
• How it was cast: the chart’s reading says, for each of its two stars, whether the replacement star took the centre, and whose it was.
• Formations: the replacement chart is checked for formations of its own; it may keep the main chart’s, lose them, or show others, and the reading names what it has.

Across traditions

• Western astrology’s cusps: a birth with a planet at the very edge of a sign, or near a house cusp, is read with care, and some astrologers blend the two signs; the replacement chart is Feng Shui’s answer to the same edge.
• The Eight Mansions read only the eight directions, 45° each, and have no replacement chart: a home near a mountain’s edge keeps its house trigram unless it crosses a direction’s line.

Origin and history

The replacement charts belong to the Xuan Kong school’s more guarded teaching. Jiang Dahong alluded to them in the 17th century, and Shen Zhureng’s school set them out with the verse of the replacement stars, so that every facing near an edge could be cast both ways. Because a replacement star often leaves the period’s stars far from the sitting and the facing, many practitioners treat the edges of a mountain with extra care, and ask for the facing to be measured again.

How Ulune calculates it

Ulune measures the distance from the facing to the nearest edge of its mountain. Within 3° it casts the replacement chart beside the main one: for the mountain star and for the water star, the number going to the centre is replaced by the replacement star of the mountain that decides its flight, the mountain holding, in that number’s own palace, the place the home’s mountain holds in its own. The flight’s direction stays the same, and a 5 keeps its number. Over the 216 charts of the nine periods, the replacement leaves both centre numbers unchanged in 56, changes one in 112 and both in 48.

Correspondences