The Order of the Twelve Earthly Branches

The twelve earthly branches follow a fixed sequence: 子，丑，寅，卯，辰，巳，午，未，申，酉，戌，亥. This order is the foundation for branch numbering, yin-yang classification, timekeeping, month assignment, the sexagenary cycle, and the zodiac. Yet the same sequence is entered from different starting points depending on the application. Time begins with 子, while the calendrical year begins with 寅. The two starting points coexist within one symbol system, and confusing them is a common source of error when reading tables.

序列从子起

The basic order of the twelve earthly branches is fixed and begins with 子. In full, the sequence runs 子，丑，寅，卯，辰，巳，午，未，申，酉，戌，亥, and then returns to 子. This is the ordinal backbone against which the branches are counted. When a text speaks of the first branch or the second branch, it is referring to this sequence unless another starting point is explicitly stated.

Yin and yang are assigned according to position in this sequence. The branches in odd-numbered positions—first, third, fifth, seventh, ninth, and eleventh—are classified as yang. Those are 子，寅，辰，午，申, and 戌. The branches in even-numbered positions—second, fourth, sixth, eighth, tenth, and twelfth—are classified as yin. Those are 丑，卯，巳，未，酉, and 亥. This positional yin-yang division follows directly from the sequence starting at 子.

The twelve double-hours of the day also begin from this order. 子 hour is the first of the twelve time periods and starts at 23:00, not at midnight. From there, each subsequent branch covers a two-hour interval in the fixed order. The day is therefore anchored to 子 as the opening position of the sequence.

月份却从寅起

Months do not begin with 子. In the traditional calendrical arrangement, the first month of the year corresponds to 寅, not 子. The month assigned to 寅 begins at 立春, the start of spring in the solar terms, rather than at the lunar new year in the broader popular calendar. From 寅, the remaining months proceed through the fixed branch order: the second month is 卯, the third is 辰, and so on through 丑 as the twelfth month.

This means that the same sequence of twelve symbols has two distinct entry points. For the hours of the day, the sequence is entered at 子. For the months of the year, the sequence is entered at 寅. The order of the symbols themselves does not change; only the point at which counting begins differs.

两个起点为什么不一样

The two starting points arise because the hour cycle and the month cycle are anchored to different reference events. The daily cycle begins with 子 because 子 marks the onset of yang rebirth in the daily alternation of yin and yang. The yearly cycle begins with 寅 because 寅 marks the first month of spring, when the year’s yang growth begins to manifest after the dormant period represented by 子 and 丑. In this model, 子 is associated with the deep yin phase and the initial turning of qi, while 寅 is associated with the visible beginning of growth in the agricultural and seasonal year.

The 五虎遁 and 五鼠遁 formulas reflect this division. 五虎遁 gives the heavenly stem for the 寅 month, because the month cycle starts from 寅. 五鼠遁 gives the heavenly stem for the 子 hour, because the hour cycle starts from 子. Each formula begins from the starting point of its own subsystem. The two formulas therefore operate in parallel but are not interchangeable: one addresses the first month, the other the first double-hour.

In the sexagenary cycle, the combined counting of heavenly stems and earthly branches begins with 甲 paired with 子. From that starting pair, the ten stems cycle six times and the twelve branches cycle five times before the pair 甲子 returns. This gives sixty combinations. The sexagenary sequence is thus an expansion of the same branch order, beginning at 子 and interlocking with the stem cycle. It does not begin at 寅.

生肖顺序跟的是哪一个

The zodiac follows the fixed order of the earthly branches. In the standard correspondence, 子 is paired with the rat, 丑 with the ox, 寅 with the tiger, 卯 with the rabbit, 辰 with the dragon, 巳 with the snake, 午 with the horse, 未 with the goat, 申 with the monkey, 酉 with the rooster, 戌 with the dog, and 亥 with the pig. This pairing proceeds in the unmodified branch sequence beginning from 子.

The zodiac order is therefore not aligned with the month cycle’s starting point. It does not shift to begin with 寅 and the tiger merely because the calendrical first month is 寅. When people list the zodiac animals from rat through pig, they are listing the earthly branches in their fixed order from 子 to 亥. The tiger remains third in the zodiac because 寅 is third in the branch sequence, even though 寅 is the first month of the year. The two uses share the same symbols and the same order, but they begin counting at different places.

查表时最容易错位的一格

The most common error in looking up branch correspondences is to treat the month number as if it were the branch’s ordinal number in the fixed sequence. Under that assumption, the first month would correspond to 子, the second to 丑, and so on. That is incorrect. In the traditional month system, the first month corresponds to 寅. The second month corresponds to 卯. The third to 辰. The pattern continues through the sequence, with the twelfth month corresponding to 丑.

The error is easy to make because the branch sequence itself is so often numbered from 子. When a table lists month numbers beside branch names, a reader may instinctively align the first row with the first branch. But the correct row for the first month is 寅, not 子. The offset is therefore two positions: month one maps to branch three. Month two maps to branch four. In general, for months one through eleven, the branch position is the month number plus two; the twelfth month wraps to 丑, which is the second branch. Keeping the two starting points separate—子 for the day and the fixed sequence, 寅 for the year and the months—prevents the misalignment.