간지

천간(天干) Heavenly Stems

The ten Celestial or Heavenly Stems (Chinese: 天干; pinyin: tiāngān; Korean: 천간) are a Chinese system of ordinals that first appear during the Shang dynasty, ca. 1250 BCE, as the names of the ten days of the week. They were also used in Shang-period ritual as names for dead family members, who were offered sacrifices on the corresponding day of the Shang week. The Heavenly Stems were used in combination with the Earthly Branches, a similar cycle of twelve days, to produce a compound cycle of sixty days. Subsequently, the Heavenly Stems lost their original function as names for days of the week and dead kin, and acquired many other uses, the most prominent and long lasting of which was their use together with the Earthly Branches as a 60-year calendrical cycle.

(from "Celestial_Stem", Wikipedia)

No	Heavenly Stem	Meaning
		Original	Modern
1	甲 갑	shell	first (book I, person A etc.), methyl group, helmet, armor, words related to beetles, crustaceans, fingernails, toenails
2	乙 을	fishguts	second (book II, person B etc.), ethyl group, twist
3	丙 병	fishtail	third, bright, fire, fishtail (rare)
4	丁 정	nail(fastener)	fourth, male adult, robust, T-shaped, to strike, a surname
5	戊 무	lance	(not used)
6	己 기	threads on a loom	self
7	庚 경	evening star	age (of person)
8	辛 신	to offend superiors	bitter, piquant, toilsome
9	壬 임	burden	to shoulder, to trust with office
10	癸 계	disposed grass	(not used)

(from "Celestial_Stem", Wikipedia)

지지(地支) Earthly Brahches

The Earthly Branches are an ordering system used throughout East Asia in various contexts, including its ancient dating system, astrological traditions, and zodiac. This system was built from observations of the orbit of Jupiter. Chinese astronomers divided the celestial circle into 12 sections to follow the orbit of 歲星 Suìxīng (Jupiter, the Year Star). In correlative thinking, the 12 years of the Jupiter cycle also identify the 12 months of the year, 12 animals (mnemonics for the system), directions, seasons, and Chinese hour in the form of double hours.

No	Earthly Branch	Chinese zodiac	Direction	Season	Lunar Month	Double Hour	Western Zodiac
1	子	鼠 Rat	0° (north)	winter	Month 11	11pm to 1am (midnight)	Aries 「백양」
2	丑	牛 Cow	30°		Month 12	1am to 3am	Taurus 「황소」
3	寅	虎 Tiger	60°	spring	Month 1	3am to 5am	Gemini 「쌍둥이」
4	卯	兎 Rabbit	90° (east)		Month 2	5am to 7am	Cancer 「큰 게」
5	辰	龍 Dragon	120°		Month 3	7am to 9 am	Leo 「사자」
6	巳	蛇 Snake	150°	summer	Month 4	9am to 11am	Virgo 「처녀」
7	午	馬 Horse	180° (south)		Month 5	11am to 1pm (noon)	Libra 「천칭(天秤)」
8	未	羊 Goat	210°		Month 6	1pm to 3pm	Scorpio 「전갈」
9	申	猿 Monkey	240°	autumn	Month 7	3pm to 5pm	Sagittarius 「궁수」
10	酉	鷄 Chicken	270° (west)		Month 8	5pm to 7pm	Capricorn 「염소」
11	戌	犬 Dog	300°		Month 9	7pm to 9pm	Aquarius 「물병」
12	亥	猪 Pig	330°	winter	Month 10	9pm to 11pm	Pisces 「물고기」

Zodiac gods - images from the stone inscription of the tomb of Kim Yusin (김유신, 金庾信, 595-673)

The tomb of Kim Yusin is a large tomb measuring roughly 30m in diameter. The relief carvings of 12 Oriental zodiac gods (half man, half animal) stand guard around the tomb, brandishing weapons.

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Reference

Smith, Adam (2011). "The Chinese sexagenary cycle and the ritual origins of the calendar". In John Steele (ed.). Calendars and years II : astronomy and time in the ancient and medieval world (PDF). Oxford: Oxbow. pp. 1–37. ISBN 978-1-84217-987-1. [1]