Kokoro by Natsume Sōseki: Plot Summary, Who K Is, and Why Sensei Writes His Final Letter

Part I: "Sensei and I"

The narrator, a university student, is left alone in Kamakura during the summer after the friend who invited him is called home. At the beach he keeps noticing the same man, at first in the company of a foreign visitor, and eventually he finds a chance to get to know him. As they grow closer, he begins to call him "Sensei".

Back in Tokyo, the student visits Sensei's home and learns from Sensei's wife that Sensei goes every month to visit the grave of a friend. Over months and years the student comes to know the couple well, but Sensei keeps a certain distance. He refuses to talk about his dead friend, does not explain why he lives without a job, and warns the student that admiration and closeness will only end in disappointment. Still, he promises that when the time is right he will tell the whole story of his past.

Part II: "My Parents and I"

After graduating, the narrator returns to his family in the countryside, where his father is seriously ill. The family's plans for a graduation celebration are interrupted by news that Emperor Meiji has fallen ill, and the father follows the emperor's decline in the newspapers from his sickbed. Then comes the news that General Maresuke Nogi has taken his own life to follow his emperor in death.

Soon a telegram arrives from Sensei asking the student to come to Tokyo. He cannot leave his dying father and says no. A few days later, a thick letter arrives by registered mail. Flipping through it, he sees a line near the end saying that by the time the letter reaches him, Sensei will already have left this world. The student rushes to the station, boards the first train to Tokyo, and begins to read.

Part III: "Sensei's Testament" — the secret of K

The letter tells Sensei's own story. He lost both parents to illness in his late teens and left the family fortune in the care of his uncle while he studied in Tokyo. Eventually he discovered that much of the money had been poured into his uncle's failing businesses; he sold what was left, visited his parents' grave one last time and cut all ties with his home town.

In Tokyo he became a lodger in the quiet house of a widow and her daughter, and fell for the daughter at first sight. Yet his uncle's deceit had left him suspicious, and he held back from asking for her hand. He then invited his friend K, the son of a Buddhist priest who had been disowned for following his passion for religion and philosophy instead of medicine, to share the lodgings.

K slowly grew warmer and more sociable, and Sensei began to see him as a rival. When K finally confessed that he loved the daughter, Sensei could not answer. Instead, he reminded K of K's own ideals of discipline and devotion, and then, without telling K, he went to the widow and asked to marry her daughter. She agreed. K learned of the engagement from the widow. Before Sensei could speak to him, K took his own life during the night, leaving a note that did not contain the reproach Sensei dreaded.

Sensei married the daughter, but K's death shadowed the marriage. He kept the secret from his wife, withdrew from the world, and visited K's grave every month. With the end of the Meiji era and the death of General Nogi, he decided that he had outlived his time. His last request to the narrator is that his wife must never learn his story.

Who is K, and why does K die?

K is never given a full name. He is Sensei's friend and classmate from the same home town, a serious young man who pushes himself through a hard course of study while supporting himself, and who prizes discipline and devotion to a cause. His confession of love puts his ideals and his feelings in direct conflict.

Sensei first reads K's death as the result of lost love, but over the years he comes to believe that it was less about love and more about alienation and disappointment in oneself, the same loneliness Sensei himself suffers from. The translator Edwin McClellan argued that in this novel, "psychological guilt [is] less important than philosophical isolation".

Why does Sensei die? The main interpretations

Readers have argued about this for a century. The critic Jun Etō saw a "dual motivation": a personal wish to end years of egoistic suffering, and a public wish to show loyalty to the emperor, as General Nogi had. Etō also linked the novel's focus on isolation to a philosophical crisis Sōseki went through while studying in London. Takeo Doi read the novel very differently, as a psychological descent, and pointed to inconsistencies in Sensei's account of his uncle.

In Japan, the novel is often read alongside the idea of the "spirit of Meiji". Sōseki wrote it under the influence of General Nogi's death, and he has Sensei die along with that era as Japan moves into the new Taishō period.

Who was Natsume Sōseki?

Natsume Sōseki (1867–1916) is often called the first modern novelist of Japan. His fiction explored individualism, loneliness and the clash between traditional values and rapid Westernization in the Meiji era. After studying in London from 1900, a period of poverty and a severe nervous breakdown, he became famous with I Am a Cat (1905). In 1907 he left his university post to write full-time for the Asahi Shimbun, the paper that later serialized Kokoro.

He died in 1916 at 49, leaving his last novel, Light and Dark, unfinished, and his portrait appeared on Japan's 1,000-yen note from 1984 to 2004. Kokoro is the last part of a trilogy that begins with To the Spring Equinox and Beyond and The Wayfarer. The Shinchō paperback edition alone had sold 7.18 million copies by 2016, the most of any book in that series.

Learn English with Kokoro

Expression	Meaning	Example
keep someone at arm's length	avoid getting too close	Sensei kept the student at arm's length.
weigh on someone's mind	make someone worry for a long time	K's death weighed on Sensei's mind for years.
a guilty conscience	the feeling that you did wrong	He visited the grave with a guilty conscience.
beat someone to it	do something before another person can	Sensei beat K to it and spoke to the widow first.
come clean	tell the truth about something hidden	In his letter, Sensei finally comes clean.

Practice: Write three sentences about Sensei using "keep someone at arm's length" and "come clean". Then write one sentence saying whether you think he should have told his wife.