1855 brought Tadamasa a great deal, good and bad. On the twenty-first day of the fifth month he showed his skill at fast riding before the shogun Iesada at the mounted review in the Fukiage garden of Edo Castle, and was commended for it. In the summer of that same year his father Tadataka fell ill at his post in Niigata.
His father Tadataka
Tadataka was not an Oguri by birth. He was the fourth son of the hatamoto Nakagawa Hida-no-kami Tadateru. When Tadakiyo, the tenth head of the house of Oguri, took to his sickbed in 1813 with no legitimate son, he noticed that Tadataka, the fourth son of the neighbouring Nakagawa, was a serious and likeable young man, took him in as his adopted son and married him to his eldest daughter Kuni. Tadataka succeeded to the house in the tenth month of the same year. As it happened, Tadakiyo, who had had no son, was given a boy just afterwards; the child was registered as Tadataka's younger brother.
Tadataka was called into the pages' corps in 1826 and rose steadily after that. He served as messenger of the shogun, became inspector of the western keep in 1842, and was given hoi rank in the twelfth month. In the seventh month of 1845 he was promoted to keeper of the castle in the shogun's absence; in the tenth month of 1847 he became captain of the bowmen; and in 1854 he was appointed commissioner at Niigata. When Tadamasa was born, Tadataka was twenty-nine and his mother Kuni seventeen.
Death at Niigata
A commissioner's post meant going out to the place and doing the work there. Tadataka too left Edo, and carried out his duties at Niigata in Echigo.
On the eighteenth day of the seventh month of 1855 Tadamasa left Edo for Niigata to visit his sick father. On the twenty-eighth day of the seventh month Tadataka died of illness in the official residence at Niigata, at fifty-eight. It was only about a year since he had taken up the post. His posthumous name was Tadatakain.
His remains were buried at Hōonji in Teramachi in Niigata, and a portion was taken to Hozenji at Ushigome Yokoderamachi in Edo, the temple that held the Oguri family graves. The grave at Hōonji was raised in the second month of 1856, cut with an inscription by Edayoshi Shin'yō, a scholar from Saga.
The succession
Three months after his father's death, on the twenty-second day of the tenth month of the same year, Tadamasa succeeded to the house of Oguri. He took the name Matakichi, borne by the heads of the house in every generation, and became its twelfth head. He was twenty-eight.
For a hatamoto house the succession meant more than one head giving way to the next: with the stipend and the duties went the head's responsibility to the shogunate. The change shows plainly in the account book Tadamasa kept himself. Entries that had been in units of one or two bu jump to one ryō one bu from the tenth month of 1855. Prices were rising, but the larger reason is taken to be that he now ran a hatamoto house of 2,500 koku alone.
There is one more thing to be read from the account book. After he succeeded, Tadamasa gave to Hozenji in Edo as a matter of course, but he also sent an offering to Hōonji, far away in Niigata, every year at the midsummer festival and at the year's end, without fail. Whether out of piety or out of duty to his dead father, neither the diaries nor the account book says. The diaries run to two or three lines on most days, setting down plain facts and nothing else, as briefly as the thing can be done.
The observance went on all his life. Thirteen years later, in the first month of 1868, with news of the defeat at Toba and Fushimi reaching Edo and the shogunate falling apart, Mukasa Yūzaemon, the head of his stewards, went to Hozenji at Ushigome Yokoderamachi to pray in his place on the anniversary of Tadataka's death. On days when the head of the house could not move for his duties at the castle, the observance was still not missed.
From here, out into the world
Twenty-eight years from his birth. The studies at the private school, the training in arms, the argument at the Tatebe house, the entry into the guard, the marriage to Michiko — everything set out so far falls within the years up to this succession. Two years after he succeeded, in the first month of 1857, he was made messenger of the shogun, and in the twelfth month he was given hoi rank, which corresponded to the junior sixth rank; ranks from the junior fifth, lower grade, upward had to be submitted to the imperial court, so this was the highest the shogunate could confer by its own order. Four years later, in 1859, Tadamasa was appointed inspector, and the next day he was ordered to accompany the embassy to the United States that was to exchange the ratifications of the Treaty of Amity and Commerce. With the voyage to America, and the first journey around the world by Japanese, his life begins to move in earnest.
Sources: Sakamoto Fujiyoshi, “Hyōgo Shōsha” o Tsukutta Saigo no Bakushin: Oguri Kōzukenosuke no Shōgai (the last shogunal official, the man who created the Hyōgo Shōsha: the life of Oguri Kōzukenosuke), Kōdansha, 1987; Ōtsubo Motoji, Oguri Kōzukenosuke Tadamasa Kakei oyobi Ryaku-nenpu (the genealogy and short chronology of Oguri Kōzukenosuke Tadamasa), Oguri Kō Kenshōkai, 1957; Ōtsubo Sadakata and Hozumi Odoroki, Oguri Kōzukenosuke, Oguri Kōzukenosuke o Shinobu Kai, 1975
→ His rise as a shogunal official, and the embassy to the United States ／ How he came to be chosen for the embassy