What does 心 Kokoro mean?

Kokoro names the seat of a person's inner life. English has to decide whether that means the heart or the mind, and Japanese does not, which is the entire difficulty and the reason translators quarrel over it.

One character, three English words

心 is written with four strokes and turns up constantly. It covers emotion, in the way English heart does. It covers thought and attention, in the way English mind does. It covers character and spirit, in the way English uses heart again in phrases about courage.

The compounds show the range. It appears in words for worry, for intention, for being attentive to someone, for sincerity, and for the centre or core of a thing. A word that generates vocabulary about both anxiety and centrality is not doing a job either English word does alone.

What the translations give up

Rendered as heart, the thinking disappears and the result sounds more sentimental than the original. Rendered as mind, the feeling disappears and the result sounds colder. Rendered as spirit, it picks up a religious edge the Japanese does not necessarily carry.

Every choice is a loss, and the losses point in different directions, which is why the same line can appear in two translations that seem to describe different states.

Sōseki, and why the title stayed

Natsume Sōseki published a novel called Kokoro in 1914, and English editions have generally kept the Japanese title rather than translating it. That decision is itself the argument: a novel concerned with guilt, isolation, the reticence of one man and what he cannot bring himself to say could not be called Heart without becoming a different book, or Mind without becoming an unreadable one.

Publishers who face the problem directly tend to leave the word alone, which is the strongest available evidence that the hole in English is real rather than a translator's excuse.

The shape of the hole

English inherited a split between reason and emotion and built vocabulary on both sides of it. Head and heart are opposed in idiom, and a person can be told to follow one rather than the other, which presumes they are separable and sometimes at war.

Japanese has words for the intellect specifically when it wants them. What it also has is this, a term that declines to make the division, so a sentence can describe a person's whole interior without first sorting it into departments. That is not a mystical property of the language. It is one word covering territory English divided up, and the division is the thing that is culturally particular, not the word.