East Asian age reckoning originated in China and continues in limited use there and in Japan, but is still common in Korea. People are born at the age of one, i.e. the first year of lifetime using ordinal number (instead of "zero" using cardinal number), and on Chinese New Year or New Year's Day one year is added to their age. Since age is incremented at the beginning of the lunar or solar year, rather than on the anniversary of a birthday, people may be one or two years older in Asian reckoning than in the international age system.
In either the traditional or modern age system the word sui (traditional Chinese: 歲; simplified Chinese: 岁; pinyin: suì), meaning "years of age", is used for age counting. When a person's age is given in a publication, it is often specified whether it is his or her:
Of the three, only 周歲/周岁 (Chinese), zhōusuì (pinyin) = "round age" may be used as a count word.
When a child has survived one month of life (29 days if lunar month reckoning) a mun yuet (Chinese: 滿月; pinyin: mǎnyuè) celebration can be observed, in which duck or chicken eggs dyed red are distributed to guests to signify fertility.
The traditional Japanese system of age reckoning, or kazoedoshi (数え年, lit. "counted years"), which incremented one's age on New Year's Day, was rendered obsolete by law in 1902 when Japan officially adopted the modern age system, known in Japanese as man nenrei (満年齢). However, the traditional system was still commonly used, so in 1950 another law was established to encourage people to use the modern age system.
Today the traditional system is used only by the elderly and in rural areas. Elsewhere its use is limited to traditional ceremonies, divinations, and obituaries.[original research?]
Japanese uses the word sai (歳 or 才) as a counter word for both the traditional and modern age system.
Koreans who use the traditional system refer to their age in units called sal (살), using Korean numerals in ordinal form. Thus, a person is one sal ("han sal", 한살) during the first calendar year of life, and ten sal during the tenth calendar year.
The 100th-day anniversary of a baby is called baegil (백일, 百日) which literally means "a hundred days" in Korean, and is given a special celebration, marking the survival of what was once a period of high infant mortality. The first anniversary of birth named dol (돌) is likewise celebrated, and given even greater significance. South Koreans celebrate their birthdays, even though every South Korean gains one 'sal' on New Year's Day. Because the first year comes at birth and the second on the first day of the New Year, children born, for example, on December 29 will reach two years of age on the New Year's Day, when they are only days old. Hence, everyone born on the same calendar year effectively has the same age and can easily be calculated by the formula: Age = (Current Year − Birth Year) + 1
In modern South Korea the traditional system is used alongside the international age system which is referred to as "man-nai" (만나이) in which "man" (만) means "full" or "actual", and "nai" (나이) meaning "age". For example, man yeol sal means "full ten years", or "ten years old" in English. The Korean word dol means "years elapsed", identical to the English "years old", but is only used to refer to the first few birthdays. Cheotdol or simply dol refers to the first Western-equivalent birthday, dudol refers to the second, and so on.
The traditional system has not been used in modern North Korea since the 1980s.
The Korean Birthday Celebrations by the lunar calendar is called eumnyeok saeng-il (음력 생일, 陰曆生日) and yangnyeok saeng-il (양력 생일, 陽曆生日) is the birthday by Gregorian calendar.
For official government uses, documents, and legal procedures, the international system is used. Regulations regarding age limits on beginning school, as well as the age of consent, are all based on this system (man-nai). The age limit for tobacco, alcohol use are after January 1 of the year one's age turns to 19.
In Eastern Mongolia, age is traditionally determined based on the number of full moons since conception for girls, and the number of new moons since birth for boys.
Koreans are considered one year old at birth and added another year at New Year’s....some Koreans may use American age counting convention while others still follow Korean convention. To eliminate this confusion, Korean asked “만나이(Man-nai)’: the same as the U.S. age counting convention.
시기나 햇수를 꽉 차게 헤아림을 이르는 말.(trans. The word refers to calculating full years or periods.
Ⅰ. (명사) 어린아이가 태어난 날로부터 한 해가 되는 날. (Ⅱ ) 1. 생일이 돌아온 횟수를 세는 단위. 주로 두세 살의 어린아이에게 쓴다. 2. 특정한 날이 해마다 돌아올 때, 그 횟수를 세는 단위.
최근 이승엽의 아버지 이춘광씨는 보통 양력생일을 치르는 요즘의 추세와 달리 이승엽의 음력 생일(1976년 8월18일)을 치르는 사연을 밝혀 화제가 됐다 (trans. It was a recent topic that Lee Chun-gwang, the father of Lee Seung-Yeop, revealed the reason why Lee Seung-Yeop takes his lunar birthday on August 18, 1976 instead of the solar birthday as opposed to the current trend.)
한국의 경우 만 20세로 성년이 되며(민법 제4조)...연령의 계산은 민법 제155조 이하의 규정에 의하나, 출생일을 산입한다(동법 제158조). 1977년의 민법 개정으로 혼인에 의한 성년의제(成年擬制)의 제도를 도입했다..대통령선거법·국회의원선거법·국민투표법·지방자치법·지방의회의원선거법·미성년자보호법 등에서는 이 원칙이 적용되지 않는다.
"청소년" 이란 만 19세 미만인 사람을 말한다. 다만, 만 19세가 되는 해의 1월 1일을 맞이한 사람은 제외한다.