The Life of Yul-Gok
Yi I was born on 26 December 1536 in Pukp'yong, in Kangwon Province. He was a child prodigy who knew Chinese script at the age of three and composed poems in Chinese before he had reached his seventh birthday. By the age of seven, he had finished his lessons in the Confucian Classics, and he passed the Civil Service literary examination at the age of 13.
At the age of 29, Yi I passed a higher Civil Service examination - with full marks - and he started government service. He wrote a thesis on the subject of Ch'ondoch'aek which was widely regarded as a literary masterpiece, displaying his knowledge of history and the Confucian philosophy of politics, and also reflecting his profound knowledge of Taoism.
He took the pen name Yul-Gok (meaning "Valley of Chestnuts") and continued his studies to grow into a great Confucian scholar, revered as the "Greatest Teacher in the East".
At 34, Yul-Gok authored "Tongho Mundap", an eleven article treatise devoted to clarifying his conviction that righteous government could be achieved even within his own lifetime, showing his aspirations and also measures to achieve it.
Yul-Gok temporarily renounced the world by secluding himself in the Diamond Mountains following his mother's death when he was 36. It is not known why he did this, although it is thought that either: he sought three years of lamentation until the Buddhist phrase, "life is transient", eased his sorrow; he may have understood that the Confucian teaching, "preserve your mind and nurture your nature", was synonymous with the Buddhist teaching, "open your mind and see your nature"; or he may have regarded it as a pleasure simply to retire to the countryside to rest.
Following his return to society, he authored "The Essentials of Confucianism" in 1576, which was considered to be a most valuable book, showing examples for a good Confucian life.
Yul-Gok died in 1584, and the valuable Yul-Gok Chônjip ("The Complete Works of Yul-Gok") was compiled after his death on the basis of the writings he bequeathed.