Nagao Masakage served as a bushō during the Sengoku period.  Masakage was the head of the Ueda-Nagao clan and lord of Sakato Castle in Echigo Province.  He was the father of Uesugi Kagekatsu.

In 1526, Masakage was born as the son of Nagao Fusanaga.  Having the lineage of the Ueda-Nagao clan, he was a distant relative of Nagao Kagetora (later known as Uesugi Kenshin).  His grandmother on his father’s side was a daughter of the Jōjō-Uesugi family.  His wife, Sentōin, was the daughter of Nagao Tamekage and the older sister of Kagetora (of a different mother).

In 1547, when a dispute erupted between Kagetora and Nagao Harukage in the Fuchū-Nagao family, Masakage sided with Harukage.  The Koshi-Nagao family who were opposed to the Ueda-Nagao family supported Kagetora.  In the twelfth month of 1548, Harukage transferred headship of the clan to Kagetora and retired.

In 1550, owing to dissatisfaction with the family succession, Kagetora launched a rebellion.  In 1551, Masakage incurred a fierce attack from Kagetora and surrendered.  This is known as the Siege of Sakato Castle.  At this time, to validate the settlement, Masakage received as his formal wife Ayahime (Kagetora’s older sister later known as Sentōin).

Thereafter, Masakage was active as a senior retainer of Kagetora, leading Ueda forces under his command.  In 1556, when Kagetora sought to abandon the headship of the clan and enter the priesthood, Masakage convinced him to stay and revert to his position.  In 1560, he was assigned to be the steward of Kasugayama Castle and served meritoriously.

On 7/5 of Eiroku 7 (1564), Masakage drowned in the Nojiri pond near Sakato Castle.  He was thirty-eight years old.  As to the reasons for the drowning, there is a theory that, in a drunken state, he fell out of a boat while enjoying merriment.  Alternatively, upon orders of Kenshin, he was murdered by Usami Sadamitsu or by Shimodaira Yoshinaga.  In any event, the details are uncertain.  In an account from the mother of a retainer, Kokubun Hikogorō, who was on the boat with Masakage, there was a wound below the shoulder on his recovered remains.  Hikogorō is said to have also died in this incident.

There is another theory that he drowned in Lake Nojiri near Nojiri Castle commanded by Sadamitsu.  In fact, Masakage’s grave was built on the shore of Lake Nojiri but was moved to its current location at the Shinkō Temple near Lake Nojiri after numerous incidents of individuals falling from horses in front of the grave.  In the city of Minami-Uonuma in Niigata Prefecture, there is a gravesite for Masakage on the former site of the Ryūgon Temple.

Owing to the early death of his eldest son, Yoshikage, the headship of the clan was inherited by his second son, Akikage (later known as Uesugi Kagekatsu).  Akikage, however, was adopted by Kenshin so, through combination with the Yamanouchi-Uesugi family, the Ueda-Nagao family itself was, in fact, extinguished.

Anecdotes

As a leader in the family, Masakage managed internal affairs but the indecisiveness of his father, Fusanaga, invited scorn, giving rise to a discriminatory sentiment toward members of the Ueda-Nagao family that lasted until the era of Fusanaga’s grandson, Akikage (Kagekatsu).

Masakage enjoyed a smooth relationship with his formal wife, Sentōin.  At the Jōkei Temple in the city of Yonezawa, there is a hanging scroll with a portrait of Nagao Masakage and his wife.  In the upper part are the mortuary tablets of the couple and the Buddhist names of Sentōin’s family and a depiction of the coming of Amida Buddha to welcome their spirits.  Owing to the young and informal appearance of Sentōin, it is surmised that she painted the scroll after the death of Masakage.  The Buddhist names of many family members lost during a succession struggle in the Uesugi family known as the Otate Conflict were separately added to pray for their souls over a long period.