He was born in Edo, a son of Yanagisawa Yasutada, who served Tokugawa Tsunayoshi, lord of Tatebayashi in Kozuke. His father's family is said to have descended from old Takeda retainers of Kai. At his birth the family held no great power. His first name was Yasuaki.
Succeeding his father, he served Tsunayoshi of Tatebayashi among his pages. Under the learning-loving Tsunayoshi, Yoshiyasu studied Confucianism diligently. Bound closely to Tsunayoshi through learning, he laid the base of his later rise.
The 4th shogun Ietsuna died, and his brother Tsunayoshi became 5th shogun. Yoshiyasu followed him into Edo Castle as a shogunal retainer. Serving close to the shogun, he gradually rose in rank.
He was appointed sobayonin, the chamberlain conveying the shogun's will to the senior councilors, and became a daimyo. Linking shogun and councilors, he gained great influence over government. Tsunayoshi's rule is known as civil government valuing learning.
He became lord of Kawagoe in Musashi and was given rank equal to a senior councilor. Trusted so much that the shogun often visited his mansion, he saw his lands steadily grow. Yet his swift rise drew envy, and later judgments of him are divided.
He took the young Confucian scholar Ogyu Sorai into his service. Sorai later became a great scholar who founded his own school of ancient rhetoric. Yoshiyasu generously supported scholars and himself loved Zen and waka, known also as a man of culture.
Tsunayoshi gave him the Matsudaira surname and the character yoshi from his own name, and he became Matsudaira Yoshiyasu, a sign of the shogun's deep trust. Around then the lord of Ako, Asano Takumi no kami, drew his sword in the castle, and Yoshiyasu is said to have been involved in judging the Ako ronin two years later.
At his Komagome mansion in Edo he completed, after seven years, the Rikugien garden, a landscape of the world of waka. It recreated famed sights such as Wakanoura in Kishu and reflects his deep love of poetry. The garden still survives in Tokyo.
When Tokugawa Tsunatoyo, later Ienobu, lord of Kofu, was named Tsunayoshi's heir, Yoshiyasu succeeded him as lord of Kofu in Kai, ruling over 150,000 koku. Entering Kai, the land of his ancestors, was a great honor for him.
When Tsunayoshi died and Ienobu became 6th shogun, Yoshiyasu promptly resigned and retired. The new government was led by Arai Hakuseki and others, and Tsunayoshi-era measures such as the Laws of Compassion for Living Things were revised. Yoshiyasu quietly withdrew from power.
In retirement he spent quiet days at Rikugien with waka and Zen, and died in Edo. Often portrayed as a man who abused power, he is now reassessed as a capable official who faithfully carried out the shogun's will.
Ogyū SoraiTokugawa TsunayoshiArai Hakuseki
Tokugawa TsunayoshiChikamatsu MonzaemonArai HakusekiOgata KōrinOgiwara ShigehideŌishi Kuranosuke (Yoshio)Ichikawa Danjūrō ITokugawa Ienobu
People of the Edo period ・ People by period
Based on facts found in textbooks and biographies. Uncertain points are marked as such.