Tian Wu: a minor star that cycles with the lunar month

Months one, five and nine: counting in fours

For anyone born in the first, fifth or ninth lunar month, the Tian Wu (天巫) of the chart sits on the same branch: the Snake. The second, sixth and tenth months put it on the Monkey, the third, seventh and eleventh on the Tiger, and the fourth, eighth and twelfth on the Pig.

Open the full-size diagram

Sketch: the landing spots are taken from the site engine for all twelve months, and each month has exactly one spot.

The four spots are highlighted and the line under the ring names the months for each: from month one the order is Snake, Monkey, Tiger, Pig, and month five returns to the Snake before two more laps follow. These four lines are copied from the comment on the Tian Wu step of iztro, the open-source Zi Wei library that the site's charts rely on. Our translation:

Months one, five and nine on the Snake; two, six and ten on the Monkey; three, seven and eleven on the Tiger; four, eight and twelve on the Pig.

Nothing in the three volumes of the old compendium Zi Wei Dou Shu Quan Shu (紫微斗数全书) names Tian Wu. So this article records only how the engine places the star and does not invent imagery for it.

Twelve months, one road walked three times

Lay the twelve months out in three rows of four and the rows turn out identical: the first month of each row is on the Snake, the second on the Monkey, the third on the Tiger and the fourth on the Pig.

So there is no need to memorize twelve entries. Divide the month number by four and read off the remainder.

1. 1

   Convert to the lunar month

   Turn the Gregorian birthday into a lunar month; for a leap month the setting decides which month it counts as.

2. 2

   Divide by four, read the remainder

   Remainder 1 is the Snake, 2 the Monkey, 3 the Tiger, and an even split the Pig.

3. 3

   Name the palace last

   Once the branch is fixed, check where Life sits to learn what that spot is called.

Four spots, and the same branch set as Tian Ma

The Tiger, Snake, Monkey and Pig branches each sit two branches apart, which draws four equal quarters on the twelve palaces. The same set of branches turns up elsewhere too: in the twelve life stages, Wood, Fire, Metal and Water begin their cycles on the Pig, Tiger, Snake and Monkey respectively, and Tian Ma lands on exactly these four.

Tian Wu reads the month and Tian Ma reads the year, so the inputs differ. The two sets of spots overlap because both rules draw on the same group of branches. Tian Ma's rule sits beside several other supporting stars in the supporting, malefic and minor stars article.

Which month counts: the new moon changes it, leap months turn on day fifteen

The input is the lunar month, not the solar-term month. February 9, 2024 was the thirtieth of the last lunar month of 2023, and Tian Wu sits on the Pig; the next day, February 10, was the first day of the first month of 2024, and the star jumps to the Snake. The year and its stem also changed that day, but Tian Wu responds to the month alone.

A leap month raises one more question. The site's default is to count a leap-month birthday on or before the fifteenth as the same month, and from the sixteenth as the next month. Take the leap sixth month of 2025: on its fifteenth day (August 8) Tian Wu is on the Monkey, as in month six; one day later, on the sixteenth (August 9), it has jumped to the Tiger, as in month seven.

If the setting is switched so that the whole leap month counts as itself, the days after the fifteenth stay on the Monkey. In a leap-month chart the stars that follow the month change places together. From the sixteenth, for example, the month-placed Tian Yue (天月), not the helper star of the same romanization, Tian Yue (天钺), moves from the Rabbit to the Pig, Jie Shen (解神) from the Rat to the Tiger and Tian Wu from the Monkey to the Tiger. So confirm the setting first and compare charts second; the background of that setting is in why leap months, hours and the day boundary change a chart.

One month, but the palace name follows the hour

Tian Wu gets its branch from the month alone, but the palace names on the chart come from Life, and Life moves with both month and hour. Two people born in the same month have Tian Wu on the same branch while the palace name often differs.

The three months fall on three different remainders and Tian Wu on three different branches. Even on the same branch, say the Monkey, the palace name there changes as soon as Life moves. When reading Tian Wu, write the branch first and the palace name second, as two separate steps.

How the other minor stars are placed, by year or by month, is laid out in the table of minor-star inputs; the next star that follows the month is Tian Yue.