Luopan

Meaning

The luopan, 羅盤 luópán, is the compass of Feng Shui. Its name is usually read as the plate that nets everything, 包羅萬象, heaven and earth held in its rings. At its heart a magnetic needle floats in a small round well, the heaven pool, 天池; around it a round dial turns on a square base, and two red threads crossed over the dial mark the reading.

The rings carry the whole of the compass schools’ vocabulary. The eight trigrams, in their Earlier and Later Heaven orders; the twenty-four mountains, often three times over on rings turned half a mountain apart; the sixty dragons, the sixty-four hexagrams, the twenty-eight lunar mansions, the solar terms and the degrees, three hundred and sixty or, on older plates, the three hundred and sixty-five and a quarter of the Chinese circle. A master’s luopan may hold forty rings; a student’s, a dozen.

It is read simply. The base is set square to the front wall of the building, the dial is turned until the needle lies over the line in the heaven pool, and the thread crossing the dial shows the facing on every ring at once: the mountain, its trigram, its star.

In practice

• Ulune’s luopan: the Home lens draws a luopan of four rings, the degrees, the twenty-four mountains, the eight directions with their trigrams and the heaven pool, with the facing mountain tinted and the sitting one drawn dashed.
• Magnetic, as a luopan reads: Ulune reads the facing from magnetic north, like the needle; a bearing from a map is turned magnetic first.
• The phone as a needle: on a phone, the device’s own compass can stand in for the needle; three readings a step apart, away from metal, give the facing, and nothing leaves the device.
• A real luopan is still the surer instrument: a phone near metal can read 20° off, and Ulune suggests checking with a compass when one is at hand.

Across traditions

• The European compass appears in writing a century after Shen Kuo’s needle, in Alexander Neckam’s notes of about 1190; the mariner’s rose divides the circle into 32 points, the luopan into 24 mountains.
• The astrolabe of the medieval Islamic and European worlds, also a disc of rings read with a rule, measured the sky; the luopan measures the ground under it.
• The diviner’s board of the Han, a round heaven plate turning on a square earth plate, is the luopan’s ancestor in form: round heaven, square earth.

Origin and history

The board came before the needle. The diviner’s boards of the Han set the branches, the stems and the corners round a square earth plate under a round heaven plate, and Joseph Needham traced the compass back to them. The Wujing zongyao, a military manual of 1044, describes a fish of magnetised iron that floats and points south; Shen Kuo, in 1088, describes a needle hung on a silk thread and notes that it points a little east of south. Over the Song, the Ming and the Qing, the needle was set at the centre of an ever richer dial, and the luopan took the form the profession still uses. Ernest Eitel described it for Western readers in 1873.

How Ulune calculates it

Ulune has no needle of its own but reads the facing as a luopan would: from magnetic north, in degrees, among the 24 mountains of the Earth plate’s ring, 15° each from Ren at 337.5°. Its dial is drawn from the same numbers, the facing marked, and on a phone the device’s compass turns it live. The edges, 3° for the replacement chart and 1.5° for the void line, are measured on that ring.

Correspondences