Rat Chinese Zodiac: Years, Elements and Compatibility

The short answer

The Rat is the first of the twelve Chinese zodiac animals — 子, the branch that runs from 23:00 to 01:00. Its years are 1924, 1936, 1948, 1960, 1972, 1984, 1996, 2008, 2020, 2032 and 2044. It combines with the Ox and clashes with the Horse. It is first in three tables — the branches, the double-hours and the sixty-term cycle, which restarts at 甲子, a Rat year — and eleventh in one.

The Rat also carries a single hidden stem, 癸, and among the six yang branches it is the only one with just one.

Your birth date tells you which of the eleven Rat years is yours and which stem it carried — all three Wood Rats, for instance, are 甲子 years.

The rest of this page is about the three explanations that come with an author behind them, and what counting gives instead of the story.

The 1984 Rat year — first of the sixty, with a leap tenth month — has its own page.

A legend first, and why it is not the answer

Ask why the Rat is first and the answer you get is usually a story. The Yellow Emperor summons twelve animals to serve as palace guards; the Cat asks the Rat to wake him and the Rat forgets; the Rat rides to the finish on the Ox's back and jumps off in front of it. The tale is retold in Chinese papers every Rat year, usually with a couplet attached: 一日时辰子为首，十二生肖鼠占头 — among the hours of a day 子 is first, and among the twelve animals the Rat takes the head.

State media are careful with that story. The long CCTV.com feature on the origin of the twelve animals puts it first among three kinds of explanation — the one drawn from legend — and adds a sentence worth keeping: the series is an ancient convention, the original reason for the order was lost long ago, and the stories told today are an after-the-fact fit to it. So this page starts where the story stops, with the three explanations that come with an author behind them:

• The double-hour reading: 子时 runs from 23:00 to 01:00, it is the first of the twelve double-hours, and the rat is the animal that comes out in it. CCTV.com attributes this reading to Zhu Xi, the Song-dynasty philosopher.
• The toe-count reading: the animals are sorted into yin and yang by whether their toes come in odd or even numbers, and the rat is the one animal that is both — four toes in front, five behind. CCTV.com names Hong Xun of the Song as its source and Lang Ying's Ming-dynasty collection as its elaboration.
• The reading in one sentence: a Ming author named Li Changqing reduces the whole business to it, and this page reproduces that sentence in full further down.

A fourth layer is easy to confuse with these and is a different kind of claim. Folk custom does not only explain the rat's position; it also likes the rat being there, and says so in objects and in festivals. That is the subject of the fifth section. After it, this page turns to the half that can be counted rather than believed: where 子 actually sits in four tables, one of which does not have it first.

The first layer: the double-hour the rat owns

The traditional day is cut into twelve double-hours, each carrying the name of a branch, and the first of the twelve is 子: 23:00 to 01:00, the two hours that straddle midnight. 子时 is the only slot in the day that belongs to two calendar days at once, which is why its usual name, 夜半, means the crossing point between one day and the next.

The pairing is explained by behaviour rather than by arithmetic, and the explanation is the same in a science page and in a government page. China's science popularisation platform, run by the China Association for Science and Technology, lists 子时 as the first of the twelve and says that this is when people are asleep and the rats come out of their holes. A county government's own account of where the animals came from walks the same twelve slots in that order and gives the reason in one line: 子时 is the two hours in which the rat moves about as the streets go quiet.

The folklorists add a purpose to the behaviour. The historian Luo Shuwei, of the Tianjin Academy of Social Sciences, puts it this way: 子时 covers eleven at night to one in the morning, and in that window the rat is the only animal that is active — so using the rat to meet daybreak is entirely reasonable. That sentence is worth pausing on, because it explains not only why the rat goes with 子 but why the first animal in the sequence is the one that meets the dawn: the sequence opens because a day opens. A separate page reads the same ring from the branch that opens the year instead.

On the ring, 子 sits opposite 午 — the Horse's 11:00 to 13:00, the middle of the day. The two hours that open the day and the two that sit at its centre are six positions apart, which is exactly the distance the classical texts give for the clash, so the slot at the head of the sequence and the slot at its centre are the same relationship read twice.

The second layer: four toes in front, five behind

The second explanation is the strangest to modern eyes and the most systematic to the people who proposed it. The twelve animals are divided into yin and yang, and the test is the toes. An animal's front and back feet normally agree in number; the rat is the exception, with four toes in front and five behind, so it is yin and yang at once — and being the only animal that is both, it takes the head of the list.

CCTV.com completes the count in the same feature: the Ox, the Goat, the Pig and the Rooster come to even numbers, the Rabbit's cleft lip and the Snake's forked tongue are drafted to the yin side to make up the six, and the Tiger, the Monkey and the Dog are odd, which with the rat makes the other six. The attribution is specific: Hong Xun, a Song-dynasty writer, is named as the source of the reading, and the Ming scholar Lang Ying as the man who tidied it in his collection of notes, where the principle is stated as 地支在下 — the branches are below, so the yin-yang tag has to be read off what is under the animal rather than off the animal itself.

Lang Ying's version is also the one that stitches this explanation to the previous one. 子时 straddles midnight: the first half belongs to the yin of the day just ended, the second half to the yang of the day beginning, and the rat — even in front, odd behind — is the one animal that fits a double-hour with a foot on each side of the line. Two explanations, in other words, are the same argument seen once from the calendar and once from the animal.

Two things are worth saying plainly about it. The count is not accurate biology: a rat's front foot carries five toes, one of them small and easy to miss, which is a reminder that what is being explained is a convention rather than a skeleton. And the explanation is a rationalisation rather than a record — it justifies an order that was already in use when it was written. The Shuihudi bamboo slips, buried in 217 BC, already pair 子 with 鼠, and the animals on them are not all the ones we use (the Horse's slot holds a deer), so the pairing was old and still settling when these explanations were being written. They tell you what the order meant to the people who used it, not where it came from.

The third layer: heaven opened at 子

The shortest of the three explanations is also the one Chinese outlets still quote at New Year. It comes from 李长卿, a Ming-dynasty writer, in a collection called 《松霞馆赘言》, and the passage is short enough to give in full: 子何以属鼠也？曰：天开于子，不耗则其气不开。鼠，耗虫也，于是夜尚未央，正鼠得令之候，故子属鼠。

Read literally: why is 子 attached to the rat? Because heaven opened at 子, and until something consumes that opening the qi will not come apart; the rat is a consuming creature, and as the night is not yet half over, this is precisely the rat's season — so 子 belongs to the rat. The explanation hangs on a pun that English cannot carry: the classical word for the rat as a pest, 耗虫, shares its character with the 耗 of 不耗则其气不开, so the animal that gnaws is the animal that opens the crack.

The longer version of the passage, as state media carry it, then allots a creature to every branch in the same shape: heaven opened at 子 and the Rat consumed the opening; the earth opened at 丑 and the Ox is the animal that opens ground; human life began at 寅 and the Tiger is the animal that kills. Read like that, the sequence is neither a race nor a ranking. It is a cosmogony laid out over twelve slots, and the rat has the first slot because heaven has the first slot.

Which is why historians of folklore are careful with it. Luo Shuwei, the Tianjin Academy historian quoted by Xinhua, calls this the clearest of the explanations — clearer, he says, than the attempts to settle the question with legend or with the five elements — and then gives the plain reading: the two hours from 23:00 to 01:00 are the ones in which the rat alone is active, and using the rat to meet daybreak is reasonable. The classical sentence and the behavioural one are the same claim, one dressed as cosmology and the other as natural history.

Why folk custom wants a rat at the head

The three explanations above answer the question of order. A fourth strand answers a different one — why, of all the animals, custom is content to let the rat lead — and it is the one you meet in objects rather than in books.

The reason given is fertility. The feature that traces the question records that Chinese custom holds the rat to be prolific, that the wish behind it was a large family and many descendants, and that the association is old enough to have been painted: in the album of the twelve animals by the late-Qing painter Ren Yu, the rat panel shows five rats feeding at a jar of melon seeds, and the word for seed, 籽, is a homophone of 子 — the character for a child, and also the name of the branch the rat carries. A rat with seeds is a picture of many children.

The New Year customs around the rat are the same wish in another medium. 老鼠娶亲 — the rat's wedding, which circulates in the first lunar month as a story, a woodcut and in places a street performance — is read in folk studies as a household disarming a pest by marrying it off: the rat is given a wedding so that it will leave the grain alone. The historian quoted by Xinhua makes the same point about the whole rat repertoire, calling it the wish to turn a nuisance into a festivity.

Here the Rat page differs from its siblings, and the difference is worth stating. The Rat is the only one of the twelve that is at once a household pest and the head of the order. The explanation of its position and the feeling about the animal are two separate things, and this page reports both without treating either as a statement about a person.

First in four tables, eleventh in one

Set the stories aside and the rat's position can be counted — which is more useful than it sounds, because counting turns up one place where it is not first at all.

It is first in the twelve branches: 子, 丑, 寅, 卯 and so on is the order the ring is built in, and the animals are names hung on it. It is first in the double-hours, for the reasons given above. And it is first in the sixty-term cycle — 甲子, 乙丑, on to 癸亥 — and because 甲子 is a Rat year, the cycle that restarts every sixty years restarts on the rat. The Purple Mountain Observatory, which drafts China's calendar standard, lists the sixty combinations in that order when it explains how years and days are named.

And it is eleventh in the months. The first month belongs to the Tiger, and 子月 is the eleventh month, the one that contains the winter solstice. This is stated flatly in the national standard GB/T 33661-2017, whose rule is that the lunar month containing the winter solstice is the eleventh; the observatory's own science staff give the same line; and the classical compendium agrees in its chapter on the months, which writes 十一月建子 — the eleventh month is built on 子.

Why do the months start elsewhere? Because a calendar year starts in spring, and the arrangement is called 夏正建寅, the Xia reckoning with the year opening in the Tiger month. It was not always so: the Zhou opened the year in 子 before the Western Han moved it back to the Tiger, and the reform that fixed the first month as the one containing the rain-water term is the one still in use. So of the four counts, three begin at the rat and one begins at the Tiger — and the one that begins at the Tiger is the only one of the four that a person can be born into. That is the useful part of counting: the rat is not first in the abstract. It is first in three tables, and the fourth is a decision.

Rat Compatibility: Six Positions in the Pairing Table

Every branch takes six positions in the classical relationship table, one for each rule that can name it, and for the rat five of those positions are written out in five separate chapters of one Ming compendium, Sanming Tonghui:

• Six Harmony (六合): Ox
• Three Harmony (三合): Dragon, Monkey
• Clash (六冲): Horse
• Harm (六害): Goat
• Punishment (三刑): Rabbit

Read the chapters together and each rule is a different piece of arithmetic on the same ring. The combinations are pairs. The Three Harmony is a set of three that will not form if one is missing — 申, 子 and 辰 make the water frame, and the compendium says outright that a frame with a piece missing does not form at all. The clash and the punishment are distances, and the same book gives all three numbers in one line: seven for the clash, ten for the punishment, six for the combination. It also gives the pair 子 and 卯 a name of its own, the punishment of no ceremony, and the rat's chapter adds a detail that is easy to miss: it says that 子 uses 癸 alone, which is the sentence the next section leans on.

The rat's sixth position is the one it does not have. Four branches punish themselves — 辰, 午, 酉 and 亥 — and the compendium does not list them; it derives them, as what is left over when the three punishment pairs are taken out of each group of four. 子 is not among them, because 卯 is its partner. Of the five partners above, two have pages of their own on this site: the Dragon, one of its Three Harmony set, and the Horse, the branch it clashes with. Both read the same table from their own side, and the full 144-pair chart is the table itself.

One hidden stem, and it is a yin one

Every branch carries a set of heavenly stems underneath it, and most carry two or three. The rat carries one: 癸, yin water. The classical material says so twice — the verse that lists the hidden stems gives 子 as holding 癸 water and nothing else, and the chapter on punishment says it while explaining why 子 and 卯 punish each other: 子 uses 癸 alone.

The reason is positional. The four cardinal branches are 子, 午, 卯 and 酉, one for each solstice and equinox, and the reference works give the same shape of reason for each of them: 子 is where 癸 is strongest, so 癸 is what it holds. Three of the four cardinal branches carry exactly one stem — 子, 卯 and 酉 — and 午 is the exception, carrying two.

What makes the rat's case worth a section is the mismatch. The chapter on the combinations opens by sorting the branches: 子, 寅, 辰, 午, 申 and 戌 are yang, and the other six are yin. So 子 is a yang branch, and the stem it holds is 癸, which is yin water. That is not a mistake to be smoothed away, and it is not as lonely as it first looks: among the six yang branches, 子 is the only one carrying a single hidden stem. The other five carry two or three. A yang branch that holds exactly one stem, and holds a yin one, is a property the rat has and nothing else on the ring does.

Eleven Rat years, and the two lines a Rat year starts on

Rat years arrive every twelve years, and the element they carry comes from the year's heavenly stem. Between 1924 and 2044 there are eleven of them.

Five forms appear, and they are not evenly spread: the Wood Rat comes round three times — 1924, 1984, 2044 — while each of the other four appears twice. Read down the form column and the order never varies: Wood, Fire, Earth, Metal, Water. That is the generating order of the five elements, and it appears here for a plain reason: twelve years pass between one Rat and the next, and a stem cycle is ten, so each step down the table advances the stem by two.

There is a harder pattern underneath, and it decides which stems a Rat year can carry at all. 子 is counted among the six yang branches, and the classical pairing gives a yang branch only yang stems — 甲, 丙, 戊, 庚, 壬. Those are exactly the five in the table, so no Rat year carries 乙, 丁, 己, 辛 or 癸. The consequence is worth stating on its own: every Wood Rat is 甲子. The three Wood Rats in that table are the three times the sixty-year cycle restarts, and 1984 is one of them.

Where a Rat year starts is a second question, and it has two answers in current use. China's national standard for the calendar, GB/T 33661-2017, drafted by the Purple Mountain Observatory, starts the lunar year at the first month, and the animal year shares that reference: under the standard the animal changes on Lunar New Year's Day. Chart reading changes the sexagenary year at Li Chun, the solar term that opens spring, which falls on 3, 4 or 5 February. The standard's own worked example is a Rat year — the lunar year running from 2 February 1984 to 19 February 1985 is 甲子 — and in 1984 the two lines fall two days apart, so a birth on 2 or 3 February is a Rat under one reading and a Pig under the other. The gap is not fixed: in 2020 Lunar New Year's Day was 25 January and Li Chun 4 February — ten days apart.

One naming wrinkle comes with those tables. The Hong Kong Observatory's conversion tables render 子 as Mouse rather than Rat — 1984 is headed Jia-zi, year of the Mouse, and 2020 Geng-zi, year of the Mouse. Both are the same branch. If you have seen a Chinese zodiac chart that writes mouse where this page writes rat, that is why.

Where this page can be wrong

Four places, stated plainly rather than buried.

The explanations come first, because this page leads with them. None of the three is a record of how the order was decided; each is a rationalisation written by someone who inherited an order and set out to make it make sense, and the state feature this page draws on says as much — the arrangement is ancient, its original reason was lost, and the stories told about it now are an after-the-fact fit. One of the three also fails its own test: a rat's front foot has five toes, not four. What can be said for all three is that they are attributable — a Song philosopher, a Song writer named Hong Xun, a Ming scholar named Lang Ying, a Ming author named Li Changqing — and that this page did not invent any of them.

The relationship tables come second. The five rules on this page rest on the classical table, and classical sources do not agree on every cell. What can be said is that none of the five is a reading invented here: all five are written out in the same Ming compendium, one chapter each. Where sources conflict this page follows the algebra rather than a ranking of authorities, because the rules are positional and every cell can be recomputed.

The hidden stems come third, and this is the softest ground on the page. The single-stem reading of 子 is what the historical dictionaries and the mainstream chart tradition carry, and it is what this site's own engine uses. Other tables allot a branch's contents differently, and the same compendium shows how: its chapter on the month's ruling element parcels the month of 子 into seven days of 壬 and twenty-three of 癸 — two stems, because it is answering a different question, about how a month's influence is distributed rather than what a branch holds. If a chart you have seen puts more than 癸 under 子, this is usually why.

The dates come last. This site computes Li Chun with a short astronomical series that is accurate to minutes rather than seconds, and the two examples above were chosen for being wide — two days in 1984, ten days in 2020. For a birthday in mid-February the choice of line changes nothing; for a birthday at either end of the window it changes everything. Nor are the two lines competing answers to one question: one is the state's rule for naming a year, the other is the convention this site's charts use, and both point at 子. How this site handles sources sets out the rest.