The Japanese Calendar
The three pages on the traditional Japanese calendar describe calendar basics, the lunisolar features of the calendar, and the relationship between the calendar and time and geographical direction.
The Five Elements, Ten Stems, and Twelve Branches
The classical Japanese calendar was based on a complex cosmological system imported from China. At the core of this system were the Five Elements (go-gyō) of wood (ki), fire (hi), earth (tsuchi), metal (gon; but pronounced “ka” in the system described below), and water (mizu). Each element was further divided into yang and yin aspects, the former designated by the Chinese character for “elder brother” and pronounced “e,” the latter designated by the Chinese character for “younger brother” and pronounced “to.” The result was a series of Ten Stems (jikkan). Each stem was given a separate Sinicized name, and these Sinicized readings formed the basis of a style of enumeration that is still used, for instance, in legal contracts and theater seating arrangements. Indeed, most modern Japanese will be able to rattle off the first three or four of these stems with ease, although the others may well cause trouble.
The following table lists the Ten Stems, showing their derivation from the yang and yin aspects of the Five Elements. The relevant Chinese character may be read in either Japanese or Sinicized fashion; the latter is the form used for enumerative purposes:
| Element | Japanese reading | Chinese character | Sinicized reading |
|---|---|---|---|
| Wood (yang) | ki-no-e（木の兄） | 甲 | kō |
| Wood (yin) | ki-no-to（木の弟） | 乙 | otsu |
| Fire (yang) | hi-no-e （火の兄） | 丙 | hei |
| Fire (yin) | hi-no-to （火の弟） | 丁 | tei |
| Earth (yang) | tsuchi-no-e （土の兄） | 茂 | ho |
| Earth (yin) | tsuchi-no-to （土の弟） | 己 | ki |
| Metal (yang) | ka-no-e （金の兄） | 庚 | kō |
| Metal (yin) | ka-no-to （金の弟） | 辛 | shin |
| Water (yang) | mizu-no-e （水の兄） | 壬 | jin |
| Water (yin) | mizu-no-to （水の弟） | 癸 | ki |
The Twelve Branches (jūni-shi) comprise the signs of the traditional Chinese zodiac, which were given the names of animals (the Western zodiac, of course, also contains 12 signs). These signs were used to designate hours of the day and directions (see the other pages for details). They are also the versions found today on Japanese New Year’s cards. The following table lists the signs by their English name, the conventional Chinese character used to represent the sign, the Japanese reading for each character, and the standard Chinese character currently used to represent the same animal. Note that in Japan, “未” is usually treated as signifying “sheep” rather than “goat” or “ram,” while “亥” is taken as signifying “boar” rather than “pig.”
| Sign | Chinese character | Japanese reading | Standard character |
|---|---|---|---|
| Rat | 子 | ne | 鼠 |
| Ox | 丑 | ushi | 牛 |
| Tiger | 寅 | tora | 虎 |
| Rabbit | 卯 | u | 兎 |
| Dragon | 辰 | tatsu | 龍 |
| Snake | 巳 | mi | 蛇 |
| Horse | 午 | uma | 馬 |
| Sheep | 未 | hitsuji | 羊 |
| Monkey | 申 | saru | 猿 |
| Rooster | 酉 | tori | 鶏 |
| Dog | 戌 | inu | 犬 |
| Boar | 亥 | i | 猪 |
Finally, the Ten Stems and the Twelve Branches were matched sequentially in pairs — always with one of the Five Elements first, beginning with wood, or ki — to yield a total of 60 possible combinations. This method of sequential matching provided the system as a whole with its name: the Eto （干支, or “Stem-Branch”）System. This system is most commonly used today to identify the year of a person’s birth, so that when an individual has completed the entire cycle of 60 and reached the year with the same sign as that person’s year of birth, it is referred to as the person’s kanreki (that is, having reached the 61st calendar year of one’s life, although now kanreki is usually used simply to refer to one’s 60th birthday). The possible permutations are as follows:
| Year | Compound | Eto reading | Sinicized reading |
|---|---|---|---|
| 1 | 甲子 | ki-no-e ne | kōshi / kasshi |
| 2 | 乙丑 | ki-no-to ushi | itchū |
| 3 | 丙寅 | hi-no-e tora | heiin |
| 4 | 丁卯 | hi-no-to u | teibō |
| 5 | 戊辰 | tsuchi-no-e tatsu | boshin |
| 6 | 己巳 | tsuchi-no-to mi | kishi |
| 7 | 庚午 | ka-no-e uma | kōgo |
| 8 | 辛未 | ka-no-to hitsuji | shinbi / shinmi |
| 9 | 壬申 | mizu-no-e saru | jinshin |
| 10 | 癸酉 | mizu-no-to tori | kiyū |
| 11 | 甲戌 | ki-no-e inu | kōjutsu |
| 12 | 乙亥 | ki-no-to i | itsugai |
| 13 | 丙子 | hi-no-e ne | heishi |
| 14 | 丁丑 | hi-no-to ushi | teichū |
| 15 | 戊寅 | tsuchi-no-e tora | boin |
| 16 | 己卯 | tsuchi-no-to u | kibō |
| 17 | 庚辰 | ka-no-e tatsu | kōshi |
| 18 | 辛巳 | ka-no-to mi | shinshi |
| 19 | 壬午 | mizu-no-e uma | jingo |
| 20 | 癸未 | mizu-no-to hitsuji | kibi / kimi |
| 21 | 甲申 | ki-no-e saru | kōshin |
| 22 | 乙酉 | ki-no-to tori | itsuyū |
| 23 | 丙戌 | hi-no-e inu | heijutsu |
| 24 | 丁亥 | hi-no-to i | teigai |
| 25 | 戊子 | tsuchi-no-e ne | boshi |
| 26 | 己丑 | tsuchi-no-to ushi | kichū |
| 27 | 庚寅 | ka-no-e tora | kōin |
| 28 | 辛卯 | ka-no-to u | shinbō |
| 29 | 壬辰 | mizu-no-e tatsu | jinshin |
| 30 | 癸巳 | mizu-no-to mi | kishi |
| 31 | 甲午 | ki-no-e uma | kōgo |
| 32 | 乙未 | ki-no-to hitsuji | itsubi / itsumi |
| 33 | 丙申 | hi-no-e saru | heishin |
| 34 | 丁酉 | hi-no-to tori | teiyū |
| 35 | 戊戌 | tsuchi-no-e inu | bojutsu |
| 36 | 己亥 | tsuchi-no-to i | kigai |
| 37 | 庚子 | ka-no-e ne | kōshi |
| 38 | 辛丑 | ka-no-to ushi | shinchū |
| 39 | 壬寅 | mizu-no-e tora | jin’in |
| 40 | 癸卯 | mizu-no-to u | kibō |
| 41 | 甲辰 | ki-no-e tatsu | kōshin |
| 42 | 乙巳 | ki-no-to mi | isshi |
| 43 | 丙午 | hi-no-e uma | heigo |
| 44 | 丁未 | hi-no-to hitsuji | teibi / teimi |
| 45 | 戊申 | tsuchi-no-e saru | boshin |
| 46 | 己酉 | tsuchi-no-to tori | kiyū |
| 47 | 庚戌 | ka-no-e inu | kōjutsu |
| 48 | 辛亥 | ka-no-to i | shingai |
| 49 | 壬子 | mizu-no-e ne | jinshi |
| 50 | 癸丑 | mizu-no-to ushi | kichū |
| 51 | 甲寅 | ki-no-e tora | kōin |
| 52 | 乙卯 | ki-no-to u | itsubō |
| 53 | 丙辰 | hi-no-e tatsu | heishin |
| 54 | 丁巳 | hi-no-to mi | teishi |
| 55 | 戊午 | tsuchi-no-e uma | bogo |
| 56 | 己未 | tsuchi-no-to hitsuji | kibi / kimi |
| 57 | 庚申 | ka-no-e saru | kōshin |
| 58 | 辛酉 | ka-no-to tori | shin’yū |
| 59 | 壬戌 | mizu-no-e inu | jinjūtsu |
| 60 | 癸亥 | mizu-no-to i | kigai |
61 | 甲子 | ki-no-e ne [repeated] | kōshi / kasshi [repeated] |
