Is the time of the zodiac defined according to the 24 solar terms or the lunar calendar?

A person's zodiac is determined by the earthly branch of the year of birth in the lunar calendar, with beginning of spring as the boundary. Last year's zodiac was before beginning of spring, and this year's zodiac started in beginning of spring. Mice born in children, tigers born in yin years, and so on. The zodiac is also divided into yin and yang. Rats, tigers, dragons, horses, monkeys and dogs are positive; Cattle, rabbits, snakes, sheep, chickens and pigs are negative.

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