Questions people ask · The tongue
裂纹舌
Chinese medicine reads cracks as a tongue short of what should fill it. Red and cracked with little or no coat is yin deficiency: the fluids have run low, often with a dry mouth at night, warm palms and poor sleep. Pale and cracked is too little blood. Cracks under a dry yellow coat point to heat. Many people are born with cracks; on a tongue of normal colour they can simply be yours.
答
A crack is a tongue that has lost some of its fullness. The tradition reads the body of the tongue as a picture of what fills it, the fluids and the blood, and a tongue that is well filled is smooth and supple. Let the filling run low and the surface gives: fine lines first, then deeper furrows down the middle or across the sides, like a field in a dry summer.
So the tradition asks two things of a cracked tongue: what has run low, and why. The colour answers the first. Red with little or no coat is yin, the cooling, moistening side of the body, spent; it usually comes with a dry mouth at night, warm palms and soles, and sleep that breaks in the small hours. Pale is blood. Deep red under a dry yellow coat is heat that has burnt the fluids. And modern teaching adds the caution that matters most: plenty of people are born with cracks, and on a tongue of normal colour with a thin, even coat, a crack can simply be the shape of yours.
燥
The Neijing does not describe cracks. It gives the rule later readers applied to them, in its account of what each of the five weathers does to the body when it wins.
Where wind prevails, things move; where heat prevails, they swell; where dryness prevails, they dry; where cold prevails, they grow puffy; where damp prevails, the stools run soft.
The first book given wholly to the tongue, the Aoshi Shanghan Jinjing Lu of 1341, set out thirty-six tongues, and the eighth is split in the shape of the character 人, person. It reads the split as fire.
The tongue shows red, and has cracks in it shaped like the character for person … it is the sovereign fire blazing, heat and toxin flaring upward, and so it cracks.
Ye Tianshi, in the eighteenth century, read the bare tongue with the same eye. A deep red tongue that shines, with no coat at all, is to him the stomach’s yin gone: the coat is made from the stomach’s fluids, and when they are spent there is nothing left to make it from.
When the tongue is deep red, shining and bright, the yin of the stomach is gone.
Modern teaching adds one distinction the old books do not make. Cracks you were born with tend to have coat lying in them, like moss in the joints of a paving stone; cracks that come from fluids running low are usually bare, with the coat thin or gone around them. It is a rule of thumb, not a test, and the colour of the tongue still counts for more.
辨证
Five pictures. The colour of the tongue, and whether the cracks are coated, decide between them.
起居
None of that is a promise, and we make none. Cracks you were born with will stay, and are nothing to mend; the fine ones that come with a red, dry tongue are the ones the tradition expects to change.
食
慎
Questions
Often, yes. Many people are born with cracks, most often a groove down the middle, and on a pink tongue with a thin, even coat that lies in the cracks too, they are simply yours. The tradition takes notice when cracks are new, when the tongue is red with little coat or pale, or when they come with a dry mouth at night or tiredness.
Not drinking enough dries the tongue and deepens cracks that are already there, and the tradition would agree: it reads cracks as fluids running low. But it looks further than water. A red tongue with little coat is read as yin running low, which a glass of water does not refill, and is answered with sleep, moist food and less of what dries as well.
Cracks you were born with do not, and need not. Fine cracks that came with a red, dry tongue, a run of late nights or a fever are expected to fade as the fluids return, slowly, over months rather than days; a daylight photograph once a month is the fair way to tell. Deep, long-standing cracks often stay even as the tongue around them changes.
Food and heat catch in the cracks, and a deep one can become sore, especially with spice, citrus or very hot drinks. The tradition reads a sore, red, cracked tongue as heat on top of fluids that have run low. Rinse after meals and keep to milder food for a while. A crack that stays sore, bleeds or has not closed in three weeks should be seen in person.
More questions
The longer read on this — the pictures in full, the sources, and the word you may have arrived with — is Waking at three in the morning, in Common concerns.
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The reading
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