First not through strength but through wit — the Rat opens the twelve-year cycle at the darkest hour of the night, the exact turning point where the year's new light is said to begin.
If you were born in one of these years, you were born under the Rat:
The changeover falls on Chinese (Lunar) New Year, not January 1st — a date that shifts each year between roughly January 21 and February 20. Anyone born in early-to-mid January or February should check the exact date before assuming their zodiac animal.
The twelve-animal cycle paired with the twelve Earthly Branches is attested with certainty by the 1st century CE: the Han-dynasty philosopher Wang Chong describes the full animal-branch correspondence, Rat and Zǐ included, in his Lunheng ("Discourses Weighed in the Balance"). Some scholars argue the underlying cycle is considerably older, though firm textual evidence only reaches back this far with confidence.
It's worth being direct about something often glossed over: very similar twelve-animal cycles are used, with local variations, across a wide swath of Central and East Asia — by Mongolic, Turkic and Tibetan calendrical traditions, among others — and there is genuine, unresolved scholarly debate about whether the system originated in China and spread outward, developed in parallel among neighboring steppe cultures, or moved in the opposite direction. Vietnamese and some other regional traditions substitute a Cat for the Rabbit and a water buffalo for the ox, which is itself suggestive of a shared root adapted independently rather than a single fixed original spreading unchanged.
The most widely told myth behind the animal order is the Great Race: the Jade Emperor, needing to name the years, decreed that the order would be set by the sequence in which the animals arrived at his palace, crossing a fast-moving river along the way. The Rat, small and a poor swimmer, persuaded the much stronger Ox to carry it across. In most versions, the Cat made the same request and the Rat agreed to wake it in time — then either forgot deliberately or pushed the sleeping Cat into the river, ensuring the Cat missed the race entirely. As Ox neared the far bank, certain of finishing first, Rat leapt off its back at the last possible moment and scurried across the finish line ahead of it, claiming first place through timing and nerve rather than any physical advantage.
This is the folk explanation both for why the Rat leads the cycle and for the traditional enmity between cats and rats in East Asian storytelling — a betrayal myth explaining a real, observable animal rivalry, in the same way many zodiac myths elsewhere double as origin stories for something people already noticed in the natural world.
The Rat's association with the hour of deepest midnight (11pm–1am) and the branch Zǐ places it at a specific, cosmologically loaded point in Chinese correlative thought: the moment Yin reaches its absolute maximum and the very first sliver of Yang is born within it. This is expressed directly in the I Ching through Hexagram 24, Fù (復, "Return") — a single unbroken Yang line beneath five broken Yin lines, traditionally associated with the winter solstice and the eleventh lunar month, the same Zǐ position the Rat occupies in the twelve-branch cycle.
Read this way, the Rat isn't simply "first" as an arbitrary starting point — it marks the specific cosmological moment where renewal begins inside what looks, on the surface, like the year's most lifeless and depleted point. The image lines up naturally with the Rat's own reputation: unassuming, easy to overlook, and disproportionately resourceful once conditions turn.
Worth noting: correlating the twelve zodiac animals with I Ching hexagrams and the sexagenary cycle is a genuine and long-standing part of Chinese correlative cosmology, not a modern invention — but it sits alongside, rather than replacing, the more everyday personality-reading use of the zodiac most people encounter first.
Beyond the Great Race, the Rat carries a long-standing association with resourcefulness and survival — a creature that thrives by adaptability rather than force, in a landscape shaped by far larger animals. In Chinese folk symbolism the Rat is also tied to abundance and prosperity, partly through its prolific breeding and its historical association with well-stocked granaries: where there was grain to spare, there were rats — an omen read, somewhat counterintuitively to a Western reader, as a sign of plenty rather than infestation.