The twenty-four solar terms and the qin: which piece for which season

On the day called Start of Spring, a qin player takes his instrument down from the wall, wipes off the dust and tunes the strings. He has not played seriously all winter. In winter the hands are cold and the strings are tight. Today is different. Today is Start of Spring, and by the old custom it is the day to play Yangchun (阳春, "Sunny Spring").

He plays it, a short piece full of mild, drifting breeze, and puts the qin back. Next time will probably be Qingming, in early April, and the piece will be Yi Guren (忆故人, "Remembering an Old Friend").

Hardly anyone keeps this habit strictly today. But it was once part of a qin player's life, and the system of time behind it became intangible cultural heritage of humanity in 2016.

What the solar terms are

The twenty-four solar terms, jieqi (节气), are an ancient Chinese calendar system that divides the year by the sun's position on the ecliptic, its apparent path across the sky. Every fifteen degrees marks one term of about fifteen days, twenty-four in all: Start of Spring, Rain Water, Awakening of Insects, Spring Equinox, Clear and Bright (Qingming), Grain Rain, Start of Summer, Grain Buds, Grain in Ear, Summer Solstice, Slight Heat, Great Heat, Start of Autumn, End of Heat, White Dew, Autumn Equinox, Cold Dew, Frost's Descent, Start of Winter, Slight Snow, Great Snow, Winter Solstice, Slight Cold and Great Cold.

They first appear in texts from the Warring States period (475–221 BCE) and the Western Han (206 BCE–9 CE). The Huainanzi, a compendium compiled at a Han prince's court in the second century BCE, already lists all twenty-four in its chapter on astronomy, and in 104 BCE, under Emperor Wu of Han, they were written into the official calendar. Chinese people have used them ever since.

At first the terms served farming: when to sow, when to harvest, when to guard against frost, as in the saying "around Qingming, plant melons and sow beans". But they soon spread beyond the fields. They acquired poems (Du Mu's line on the drizzling rain of Qingming), foods (dumplings at the Winter Solstice, spring pancakes at Start of Spring) and rituals (sweeping graves at Qingming, honouring ancestors at the Winter Solstice), and became the way Chinese people sense the passing of time. Someone who cannot tell you today's date can still tell you "it's nearly the Autumn Equinox".

On November 30, 2016, UNESCO inscribed "The Twenty-Four Solar Terms, knowledge in China of time and practices developed through observation of the sun's annual motion" on the Representative List of the Intangible Cultural Heritage of Humanity. The reason was not its age but that it is still alive.

Qin players used it too. The sound of the qin was supposed to answer to heaven and earth, so each piece had its proper time. Here they are, season by season.

Spring: from Start of Spring to Grain Rain

Yangchun. The idiom "Yangchun Baixue" ("Sunny Spring and White Snow", meaning refined art few can appreciate) names two pieces. Yangchun depicts "all things knowing that spring has come, a mild wind drifting". Zhu Quan's Shenqi Mipu (神奇秘谱, "Handbook of Spiritual and Marvelous Mysteries", 1425), the earliest surviving printed collection of qin music, includes it, and its note says the piece "takes the sense of all things returning to spring and a mild wind rippling". It suits Start of Spring and Rain Water best, like water just released from ice.

Meihua Sannong (梅花三弄, "Three Variations on Plum Blossom"). The plum blooms from late winter into early spring. The three passages of fan yin (harmonics, made by touching the string lightly) are the blossom; the stopped notes in between are the wind and snow. Spring has arrived, but the cold has not yet gone. For the origin of the piece, see Huan Yi's three variations.

Yi Guren. Qingming is the term for tending graves and for remembering the dead. This modern piece, in the manjiao tuning with the third string lowered and full of yin and nao (narrow and wide vibrato), was written for longing.

Bijian Liuquan (碧涧流泉, "Spring Flowing in a Green Ravine"). Grain Rain brings heavy rain, and the springs in the hills rise. This Lingnan school piece from south China is crisp, brief and leaping, quite unlike the vast sweep of Liu Shui.

Summer: from Start of Summer to Great Heat

Summer pieces are mostly about water and wind.

Liu Shui (流水, "Flowing Water"). Around Grain Buds and Grain in Ear the rains are frequent and the rivers swell. The "seventy-two gun and fu", the repeated sweeps across the strings in the middle of Liu Shui, are the sound of water. For the story of Bo Ya and Zhong Ziqi, see Zhiyin: the friend who knows the music.

Xiaoxiang Shuiyun (潇湘水云, "Mist and Clouds over the Xiao and Xiang Rivers"). Summer brings many clouds and mist over the water. The clouds that kept Guo Chuwang from seeing the Jiuyi mountains were probably summer clouds (see Guo Chuwang and Xiaoxiang Shuiyun).

Zuiyu Changwan (醉渔唱晚, "The Drunken Fisherman Sings at Dusk"). After the Summer Solstice the days are long, and at dusk fishermen sing on the river. The rhythm sways like a man who has been drinking.

Feng Ru Song (风入松, "Wind in the Pines"). Traditionally attributed to Xi Kang (223–262). Sitting under a pine and playing it in Great Heat was an old way of getting through summer.

Autumn: from Start of Autumn to Frost's Descent

Autumn has the most qin pieces, because it has the most Chinese poems.

Qiufeng Ci (秋风词, "Song of the Autumn Wind"). Its text, attributed to the Tang poet Li Bai, begins:

The autumn wind is clear, the autumn moon is bright. Fallen leaves gather and scatter again; the winter crow settles, then startles once more.

Around White Dew it matches the scene exactly. It is also among the first pieces beginners learn.

Pingsha Luoyan (平沙落雁, "Wild Geese Descending on the Sandbank"). The wild geese fly south between Cold Dew and Frost's Descent. This piece shows the flock wheeling and landing on a sandbar: the harmonics are the geese in the sky, the stopped notes are the geese coming down. It survives in more versions than any other qin piece.

Qiu Hong (秋鸿, "Autumn Swan Geese"). A large work of thirty-six sections included in the Shenqi Mipu, it follows the geese through a whole autumn: taking off, crossing south, roosting, flying away into the distance. Its attribution to Guo Chuwang is disputed.

Hangong Qiuyue (汉宫秋月, "Autumn Moon over the Han Palace"). A lonely palace woman on an autumn night, around the Autumn Equinox, when the moon is fullest.

Qiujiang Yebo (秋江夜泊, "Mooring on the Autumn River at Night"). At Frost's Descent, a boat is moored on the river at night and the water has turned cold. This is the season of Zhang Ji's famous Tang poem about a night mooring near Suzhou:

The moon sets, crows caw, frost fills the sky.

Winter: from Start of Winter to Great Cold

Bai Xue (白雪, "White Snow"). The partner of Yangchun. The Shenqi Mipu's note says it "takes the sound of the austere and pure, of snow on bamboo ringing like jade". Played at the term called Great Snow, the name comes true.

Meihua Sannong returns. After the Winter Solstice the plum begins to bud, and around Slight Cold it opens. So the piece can be played twice a year, in two moods: at the end of winter, "it has opened"; at the start of spring, "it will soon fall".

Yuqiao Wenda (渔樵问答, "Dialogue between the Fisherman and the Woodcutter"). The hills and waters are quietest in winter, the best time to hear these two figures of the hermit's life talk.

Yangguan Sandie (阳关三叠, "Three Variations on the Yang Pass"). Great Cold is the last term of the year, a time of farewells. The piece sets Wang Wei's parting poem, whose last line is:

West of the Yang Pass, you will meet no old friends.

At the end of the year, someone is always leaving.

Beyond the solar terms: the hours of the day

Players also cared about the hour. The best time was a moonlit night. Wang Wei wrote of playing in a bamboo grove:

Deep in the wood, no one knows I am here; the bright moon comes to shine on me.

Bai Juyi, too, played on alone late into the night. The night is quiet, and the qin is soft.

The next best time was early morning. The Xishan Qinkuang (溪山琴况, "Qin Aesthetics of Stream and Mountain", 1641) by Xu Shangying says that "in the clear morning the air is fresh, and the sound of the qin is especially pure".

The worst were noon and after the evening meal, when people are drowsy and their hands sluggish. The logic is the same as with the solar terms: the sound is so fine that slightly wrong surroundings spoil it. The ancients divided the year and the day into compartments, and the qin appeared only in the right ones.

The five occasions not to play

Ming dynasty (1368–1644) qin handbooks, including the Taigu Yiyin (太古遗音) and Fengxuan Xuanpin (风宣玄品), record a rule called the "five occasions not to play": not in high wind or heavy rain, not in the dusty marketplace, not before a vulgar listener, not without being seated, and not without proper clothing and cap.

There is also a list of fourteen occasions when it is fitting to play: on meeting someone who truly understands your music, on meeting a congenial person, before a Daoist, in a lofty hall, on climbing a tower, in a temple, sitting on a rock, on a mountainside, resting in an empty valley, wandering by the water, in a boat, at rest under trees, when the air is clear and bright, and in a fresh breeze under a bright moon.

These lists are all about surroundings: the weather, the place, the person opposite you. The season is part of the surroundings too. The ancients were not superstitious about playing a given piece on a given day; they felt the qin's sound was too small and fine to tolerate anything unsuitable. Wind and rain drown it, a vulgar listener ignores it, and in the wrong season the mood is wrong. Play Yangchun on White Dew, in early September, and however well your hands do it, it will feel out of place.

How to use it today

No one today arranges practice by the solar terms. But the terms can do one thing: give practice a reason.

Play Yangchun on Start of Spring, Qiufeng Ci on White Dew, Bai Xue on Great Snow. Twenty-four times a year is not much. After a year the pieces and the days are matched, and practice is no longer only practice. Next Start of Spring, playing Yangchun again, you will remember the year before and everything since. The pieces become a calendar.

The solar terms were listed as heritage not because they are old but because they are alive: people still live by them. Players who play by them give them one more way to stay alive.

For the difficulty of each piece and the order in which to learn them, see Classic pieces to learn (in Chinese).