In the last two posts, I listed the ten Heavenly Stems and the twelve Earthly Branches. I think that knowledge of these things is useful. And it’s just not very difficult. Of course, if you plan to take much of an interest in Chinese history, it could be essential.

Ten times twelve equals sixty

For much of Chinese history, years were listed by a combination of the Stems and Branches. This gives us sixty years in a cycle, not a hundred and twenty, as will become clear. If sixty years doesn’t seem very helpful, remember that only the Qianlong Emperor lasted a full cycle on the throne. With a little knowledge of Chinese history, you can pinpoint all kinds of dates, or at  least work out how many years passed between certain dates within a limited span.

Firstly, we need to look at how the two sequences combine.

The inner wheel rolls round the inside of the outer wheel.

As there are twelve branches (outer wheel) and only ten stems (inner wheel), the cycle shifts by two places each turn, meaning that only half of the possible combinations of stems and branches are used. The odd-placed (red) stems only ever match up with the odd-placed (red) branches, even (yellow) stems and even (yellow) branches fit together.

The Heavenly Stem comes first, and the Earthly Branch comes second.

So the first year  in the sequence is 甲子 jiǎǐ Then come 乙丑 yǐchǒu, 丙寅 bǐngyín, through to the tenth year, 癸酉 guǐyǒu. Now the first character (the stem) returns to the beginning of the sequence: 甲戌 jiǎxū is the eleventh year of the cycle. After all twelve branches have been used, they too return to the start of the sequence giving 丙子 bǐngzǐ, the thirteenth year.

Five cycles round the twelve branches gives us sixty years. Then you start again.

Putting it into practice

Let’s look at an example of some dates usually referred to using the Sexagenary Cycle.  The First Sino-Japanese War is called 甲午战争 Jiǎwǔ Zhànzhēng. You know this took place sometime toward the end of the Qing Dynasty, but may be a little hazy about exactly when. The Xinhai Revolution 辛亥革命 Xīnhài Gémìng brought a close to the Qing. Somewhere during this period there was also the Hundred Days Reform, or 戊戌变法 Wùxū Biànfǎ. Actually, it’s not too hard to work out how these dates relate to each other.

So we have three dates in sexagenary form:

甲午战争 Jiǎwǔ Zhànzhēng

戊戌变法 Wùxū Biànfǎ

辛亥革命 Xīnhài Gémìng

Remember, our dates are in the form:

Stem – Branch

First count the number of stems from 甲 jiǎ to 戊 wù：

乙 yǐ，丙 bǐng，丁 dīng，戊 wù = 4 places¹.

If you’ve not got the Heavenly Stems fixed on the fingers – no matter; that inner wheel turns, after all. But this is where it’s useful to have the twelve Earthly Branches really nailed to those fingers.

If you’ve not managed to learn them off by heart, here’s nothing wrong with actually writing the Earthly Branches on your left hand at this stage. You need to be able move your left thumb around the circle, stopping at any of the twelve points and naming it.

As we have counted four stems, from 甲 jiǎ to 戊 wù, we now need to move four places on the Earthly Branches forward from the 午 wǔ of 甲午 jiǎwǔ:

Press the thumb of the left hand against tip of the middle finger and count clockwise, as shown…未 wèi, 申shēn, 酉yǒu, 戌 xū.

It just happens that 戌 xū is the Heavenly Branch of the year we were looking for. We  have moved forward four places –  four years – from 甲午 jiǎwǔ, to 戊戌 wùxū.

The Hundred Days Reform (戊戌变法 Wùxū Biànfǎ) came four years after the start of the First Sino-Japanese War (甲午战争 Jiǎwǔ Zhànzhēng). That was easy enough. The two dates were close together. Our inner wheel didn’t have time to complete a full turn.

Let’s have a look the next date.

How many years after 戊戌变法 Wùxū Biànfǎ did the Xinhai Revolution, 辛亥革命 Xīnhài Gémìng, begin?

First, remember, we count the Heavenly Stems – first heaven, then earth. Our staring place is 戊 wù, so we count 己 jǐ, 庚 gēng, 辛 xīn – 3 places.

Our first date was 戊戌 wùxū, so find the branch 戌 xū (hint: it’s on the little finger) with the thumb of your left hand. Count forward three places starting from 戌 xū. You should reach the base of your middle finger, which holds 丑 chǒu. This position represents the year 辛丑 xīnchǒu, three years after 戊戌 wùxū. We’ve advanced three places, which means that both the stems and the branches have advanced three places.

But we’re looking for 辛亥 xīnhài and not 辛丑 xīnchǒu.

At this point we might try counting out another ten places and find that we reach our target, but there’s an easier way.

As we have a ten and a twelve scale together, instead of advancing ten places, we can just jump back two. So from the base of the middle finger we jump checkers-style back to the base of the little finger, adding ten years as we go.

The base of the little finger is exactly where we want to be – 亥 hài, 辛亥 xīnhài indeed.

3+10=13.

The Xinhai Revolution (辛亥革命 Xīnhài Gémìng) was 13 years after the Hundred Days Reform (戊戌变法 Wùxū Biànfǎ).

You can keep jumping back two places, adding ten years at a time if you wish; 辛酉 – 23 years later, 辛未 – 33 years, etc. This saves us counting round and round the fingers. We never have to move more than a few places to find the date we’re looking for.

Switching Calendars

Sooner or later, you’re going to want to pin all this to more familiar calendar dates.

2000	2001	2002	2003	2004 甲申	2005 乙酉	2006 丙戌	2007 丁亥	2008 戊子	2009 己丑
2010 庚寅	2011 辛卯	2012 壬辰	2013 癸巳	2014 甲午	2015 乙未	2016 丙申	2017 丁酉	2018 戊戌	2019 己亥
2020 庚子	2021 辛丑	2022 壬寅	2023 癸卯	2024	2025	2026	2027	2028	2029

You may have already spotted that the first character in the sexagenary date (the Heavenly Stem) will match up with the final digit in the year as it’s conventionally written. After all, there are ten Heavenly Stems, and we step through them year by year.

As it happens, during the Common Era, or AD, the first Heavenly Stem, 甲 jiǎ, is always a year ending in 4. 1984, 1994, 2004 were all 甲 jiǎ years. A quick count on your fingers, starting from 4 – 甲 jiǎ, will tell you that years ending in zero are all 庚 gēng years.

This isn’t going to be too difficult, is it?

Any century divisible by 3(00) is going to be a 庚申 gēngshēn year. So 1200, 1500 and 1800 were all 庚申 gēngshēn years. The century year after one of these will be a 庚子 gēngzǐ year, the one before will be a 庚辰 gēngchén year. So 1900 was 庚子 gēngzǐ; and the year 2000 庚辰 gēngchén.

As 申 shēn is the monkey year, you might think of the three wise monkeys. Century years divisible by three hundred are monkey years in the common era. I’m sure you can come up with a way to remember the other two.

Let’s suppose you want to know which year 1988 was. Well, 1900 was a 庚子 gēngzǐ year, so 1960 must have been too. Remember, the Earthly Branches are fixed to your fingers, let’s free the Heavenly Stems from their moorings to save a little time:

子 zǐ is the base of the ring finger. Press here but say 庚 gēng. Now jump back twice – two places each time, remember. This takes you forward 20 years. 庚子 gēngzǐ,  庚戌 gēngxū, 庚申 gēngshēn (the tip of your little finger); this is 1980. We now need to count forwards, counting Heavenly Stems, eight places from here; 辛 xīn，壬rén，癸 guǐ，甲 jiǎ，乙 yǐ，丙 bǐng，丁 dīng，戊 wù and you should have reached 戊 wù on the second joint of your forefinger, which you know is the position for 辰 chén, so you have your answer:

1988 is 戊辰 wùchén.

Try working out some familiar dates. You’ll have it down in no time.

Stems are free to roll around,
But branches are never played.
The stems count units with the clock,
And the branches jump back a decade.^２

You’ll need to exercise a little care if you want to move to dates BCE, but it shouldn’t be too difficult to work out once you have the basics down.

¹Note: If you want to work out, say, which year of an Emperor’s reign an event took place in, you must obviously count the first year as one. This will give you the n^th year.

^２For the translation of this little piece of doggerel, I accept full responsibility. The original, and much of the above explanation came from Baidupedia. For anyone interested in other ways of working out the Sexagenary Cycle, there’s plenty more to go at.