Matsudaira Tadaaki

Who They Were

Matsudaira Tadaaki (松平忠明, まつだいら ただあきら) was a samurai and daimyo — a territorial lord — whose life spanned the end of the Azuchi–Momoyama period and the first four decades of the Edo period. He was born in 1583 in Mikawa Province, the ancestral heartland of the Tokugawa clan on the coast of what is now Aichi Prefecture. His father was Okudaira Nobumasa, a senior Tokugawa commander, and his mother was Kame-hime, a daughter of Tokugawa Ieyasu, the founder of the Tokugawa shogunate. That double inheritance — a warrior house on one side, the ruling family on the other — shaped everything about his career.

He died in Edo on 1 May 1644. The name attached to his branch of the family in the source records is 奥平松平家 (Okudaira-Matsudaira-ke), the Okudaira–Matsudaira house, a line that carried both ancestral names.

Life and Career

Tadaaki was born in Tenshō 天正 (てんしょう), year 11 of that era — 1583. The Tenshō era name was in use across the country in those years, a period when Oda Nobunaga and then Toyotomi Hideyoshi were consolidating military control of Japan. Tadaaki's grandfather on his mother's side, Tokugawa Ieyasu, was one of the two great survivors of that struggle.

His father, Okudaira Nobumasa, had been adopted into the Tokugawa orbit and married Kame-hime, which placed the Okudaira house inside the shogunal family's inner circle. Tadaaki therefore grew up as a Tokugawa relative as well as a Tokugawa retainer, a status that carried both privilege and obligation. He held the position of daimyo, meaning he governed a domain and maintained a military household of his own.

He married twice. His first wife was a daughter of Oda Nobukane, a member of the Oda family that had produced Nobunaga. His second wife was a daughter of Koide Yoshimasa. Through these marriages and through his own line he had numerous children, including sons Matsudaira Tadahiro and Matsudaira Kiyomichi, and daughters recorded under names such as Matsudaira Inuko, Matsudaira Umeko, Matsudaira Iko, Matsudaira Kayako, and Matsudaira Murihime, along with a daughter who married Fujitani Tameyoshi. The breadth of that family list reflects the standard practice of daimyo houses, in which marriage alliances were instruments of politics as much as of family.

Tadaaki lived through the decisive transition of Japanese history: the death of Hideyoshi in 1598, the Battle of Sekigahara in 1600, the establishment of the Tokugawa shogunate in 1603, and the long consolidation of Tokugawa rule that followed. He died in Edo, the shogunal capital, in 1644, by which time the Tokugawa order was firmly established.

Why They Matter

Tadaaki belongs to the generation that converted military victory into stable government. The Tokugawa triumph at Sekigahara and later at the sieges of Osaka depended on a network of related and loyal houses, and the Okudaira–Matsudaira line was one of the most closely tied to the shogunal family. A daimyo who was simultaneously a Tokugawa relative and a Tokugawa retainer occupied a position of unusual trust.

His career also illustrates how the Tokugawa managed kinship. By taking the Matsudaira name — the ancestral surname of the Tokugawa — while retaining the Okudaira identity, his house advertised both its own military heritage and its connection to the ruling line. Names in this period were political statements, and the compound label 奥平松平家 made the alliance visible in every official document.

The Name in Japanese

The full name as recorded is 松平忠明 (奥平松平家).

• Kana reading: まつだいら ただあきら
• Romaji: Matsudaira Tadaaki

Broken down character by character:

松 (まつ, matsu) — "pine." The first element of Matsudaira, and one of the most common components in Japanese surnames.

平 (だいら, daira) — "flat, level." In this surname the character is read だいら rather than its more usual ひら or へい, a shift that is typical of place-derived family names.

忠 (ただ, tada) — "loyalty, devotion." A favourite element in warrior given names, and the first half of Tadaaki.

明 (あきら, akira) — "bright, clear." The second half of the given name.

The parenthetical 奥平松平家 (おくだいら まつだいら け, Okudaira Matsudaira ke) identifies the family line rather than the individual:

奥 (おく, oku) — "inner, deep."

平 (だいら, daira) — "flat, level," the same element as in Matsudaira.

松平 (まつだいら, matsudaira) — the Tokugawa ancestral surname, repeated here to mark the house's connection to the ruling family.

家 (け, ke) — "house, family line."

So the whole label means "the Okudaira–Matsudaira house," a name that fuses Tadaaki's paternal ancestry with his Tokugawa connection.

Legacy

Tadaaki's legacy is carried by his descendants and by the house name itself. His sons Matsudaira Tadahiro and Matsudaira Kiyomichi continued the line, and his daughters were married into other warrior families, extending the network of alliances that held the Tokugawa order together. The Okudaira–Matsudaira house endured as a recognised branch of the broader Matsudaira grouping.

His life also stands as a compact example of how the early Edo daimyo class was built: through battlefield service, through marriage into the right families, and through the careful use of names that announced both ancestry and allegiance. Born in Mikawa in 1583 and dead in Edo in 1644, he lived entirely within the arc of Tokugawa ascendancy, from the wars of unification to the peace that followed.