In 1862 Oguri changed his title from Bungo-no-kami, which he had borne until then, to Kōzukenosuke. He kept that name to his death, and it is as Oguri Kōzukenosuke that he has been remembered ever since.
Three years as Bungo-no-kami
A title of this kind was not a man's to assume at will. By Ōtsubo Motoji's Oguri Kōzukenosuke Tadamasa Kakei oyobi Ryaku-nenpu, Oguri was given the junior fifth rank, lower grade, and appointed Bungo-no-kami on the twenty-first day of the eleventh month of 1859, two months after becoming inspector and ten days before he was ordered to join the embassy to the United States. Abe Dōzan's Kaigun no Senkusha Oguri Kōzukenosuke Seiden likewise records that “he rose to the rank of shodaibu and was ennobled Bungo-no-kami”. It was under this name that he crossed the ocean as one of the envoys, and the signature on the exchange of the treaty ratifications was Oguri Bungo-no-kami. The American papers wrote his name Oguro-Bungo-Nokami.
The heads of the house of Oguri, it should be added, were known in every generation as Matakichi. Ōtsubo Motoji's genealogy has it that Tadamasa, the fourth head, became a page to Ieyasu at thirteen, stood at the head of the army in battle after battle when he was grown, and was given the name Matakichi for it, which became the head's name thereafter. Oguri too took the name Matakichi when he succeeded to the house in 1855, but Abe Dōzan writes that from the 1860s he did not use Matakichi and called himself Kōzukenosuke only, the reason given in the record being to avoid sharing a name with a gentleman among the shogun's councillors.
When the change was made
On the date of the change the reference works differ. Ōtsubo Motoji's short chronology gives the fifth day of the sixth month of 1862, the day he was appointed commissioner of finance, revenue side, as the day “his name was changed to Kōzukenosuke”, while Sakamoto Fujiyoshi's Oguri Kōzukenosuke no Shōgai puts it “about the fifth month of that year”. Ōtsubo Sadakata and Hozumi Odoroki's Oguri Kōzukenosuke says plainly that the date of the appointment is not known, and then hands on a story attached to the change.
The three men who had borne the title Kōzukenosuke
What made those around him uneasy was the question of ill omen. Ōtsubo Sadakata and Hozumi Odoroki's Oguri Kōzukenosuke writes that among the men allowed the rank of Kōzukenosuke, three had been stamped with a mark of ill fortune that has not faded since: Honda Masazumi, Hotta Masanobu and Kira Yoshinaka.
Honda Masazumi He served Ieyasu and Hidetada, and rose by the autumn of 1619 to hold Utsunomiya in Shimotsuke at 155,000 koku; a bare three years later he incurred Hidetada's anger and his fief was cut. Banished to Yuri in Dewa, then moved to Ōsawa and to Yokote, he died of illness in confinement in Satake Yoshinobu's keeping, at seventy-three. There was even a popular tale that he had built a ceiling rigged to fall and kill the shogun, but the truth, the book says, seems to have been a struggle for power with Doi Toshikatsu.
Hotta Masanobu Lord of Sakura in Shimōsa at 130,000 koku. He left a memorial saying that he surrendered the 130,000 koku and begged that it be used to relieve the hard lives of the hatamoto, and went back to his own territory alone, telling none of his retainers. Matsudaira Nobutsuna, chief of the senior councillors, pronounced it “nothing but the act of a madman”, and after being moved from one place of confinement to another — Iida in Shinano, Obama in Wakasa, Tokushima in Awa — he killed himself with a pair of scissors in the fifth month of 1680, at forty-nine.
Kira Yoshinaka “Kira Kōzukenosuke” of the Chūshingura, who came to a violent end at the hands of the Akō rōnin.
None of them had lived out his natural span — so the name was ill-omened, and it would be better to decline it if it could be done. It was not unreasonable for his attendants to want to say so.
He went through with it
Oguri did not change it. Sakamoto Fujiyoshi writes that “he laughed and would not agree; by one account he answered that to lose one's life for the affairs of the country is a man's true wish”, and sees in it the rationalism natural to him, which set no store by names. Ōtsubo Sadakata and Hozumi Odoroki's Oguri Kōzukenosuke reports that Oguri answered his attendants' anxiety with a smile on his cheek, as follows.
There is nothing to worry about. If they are bad examples, let us replace them with a good one, an auspicious one. That too may be work laid on me.
Ōtsubo Motoji's short chronology likewise records that Honda Kōzuke and Kira Kōzuke were neither of them ordinary men but failed to live out their natural span, so that the name was shunned, and that Oguri, it is handed down, took pride in it.
Among the 2,700 koku of the Oguri holdings, incidentally, were the village of Gonda in Gunma district, Kōzuke, at 375 koku, the village of Shimo-Arita at 170 koku and the village of Yorokubun at 88 koku. The two hundred koku added in the tenth month of 1860 for his service with the embassy were also in Kōzuke, the villages of Mori and Kobayashi in Tano district. The village of Gonda, where the whole household would later go to live in retirement, was one of these Kōzuke holdings. No record states that this had anything to do with the change of name, however.
The name Oguri Kōzukenosuke stuck. Even writings about the embassy to the United States and the Tsushima incident, which belong to his years as Bungo-no-kami, usually call him Kōzukenosuke in later usage.
Sources: 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; Sakamoto Fujiyoshi, Oguri Kōzukenosuke no Shōgai (the life of Oguri Kōzukenosuke), Kōdansha, 1987; Abe Dōzan, Kaigun no Senkusha Oguri Kōzukenosuke Seiden (a true life of Oguri Kōzukenosuke, pioneer of the navy), Kaigun Yūshūkai, 1941
→ His repeated appointments, and four terms as commissioner of finance → Opposing an increase of stipend for Hitotsubashi Yoshinobu, and resigning