Sano Masatsuna


Sano Clan

Shimotsuke Province

Sano Masatsuna

Lifespan:  Kyōroku 2 (1529) to 4/8 of Tenshō 2 (1574)

Other Names:  Kotarō (common)

Rank:  bushō, sengoku daimyō

Clan:  Sano

Father:  Sano Yasutsuna

Siblings:  Toyotsuna, Masatsuna, Fusatsuna, Yūganji

Children:  Munetsuna, Kiryū Chikatsuna, Torafusamaru

Sano Masatsuna served as a bushō and sengoku daimyō in Shimotsuke Province during the Sengoku and Azuchi-Momoyama periods.  He was the fifteenth head of the Sano clan.  Masatsuna was known to have excelled in the art of war, managing relations between two competing powers, namely, Uesugi Kenshin and Hōjō Ujiyasu, through a long series of battles at his base at Karasawayama Castle in Shimotsuke.  Through a tenuous series of surrenders and betrayals, Masatsuna retained control of Karasawayama and preserved the lineage of the Sano family.

In 1529, Masatsuna was born as the second son of Sano Yasutsuna, the thirteenth head of the Sano clan.  According to another theory, he was the son of his older brother, Sano Toyotsuna, the fourteenth head of the Sano clan.

In 1559, after the death of Toyotsuna, Masatsuna inherited the headship and became the fifteenth head of the Sano clan.

The Sano clan was obedient to the branch of the Ashikaga clan serving as the Koga kubō.  Masatsuna initially served Ashikaga Haruuji, but as the authority of the Koga kubō waned and the Gohōjō clan expanded their power, he joined forces with Hōjō Ujiyasu.  Nevertheless, once Uesugi Kenshin of Echigo invaded the Kantō with the aim of subduing the Gohōjō, he acted in coordination with Kenshin to surround the main base of the Hōjō at Odawara Castle.  In the second month of 1560, when Hōjō Ujimasa led an army of 30,000 soldiers to attack Masatsuna at his base at Karasawayama Castle, Masatsuna stiffly resisted the assault.  After the arrival of reinforcements from Kenshin, Masatsuna succeeded in repelling the besieging forces.  When the siege of Odawara Castle by the Uesugi failed, Masatsuna soon betrayed the Uesugi and, during the Eiroku period (1558 to 1570), he defected to the side of the Hōjō and Ashikaga Yoshiuji again.

From the Eiroku to Genki eras, Masatsuna endured nine or more assaults from the Uesugi army.  Owing to his superior strategies, along with the protection afforded by a mountaintop location, he successfully defended his base at Karasawayama Castle.  This series of battles spanning over a decade is known as the Sieges of Karasawayama Castle.  On several occasions, Masatsuna surrendered to Kenshin, and depending upon the battle situation, he was compelled to settle and turn-over control of the castle as well.  As soon as Kenshin returned to Echigo, he defected again to preserve the lineage of the Sano clan.  Karasawayama Castle was situated on the eastern end of Kenshin’s sphere of influence in the Kantō.  Beginning with the Satake clan, this formed the border with the sphere of influence of other clans in northern Kantō who were subordinate to the Uesugi.  From the perspective of Kenshin, securing control of Karasawayama Castle was particularly vital for the ability of the Uesugi army to advance in the Kantō.  Therefore, for a period of time, he stationed Irobe Katsunaga, the lord of Hirabayashi Castle in Echigo, at Karasawayama Castle.  Meanwhile, to avoid being swallowed by the two great powers in the form of the Uesugi and Hōjō clans, Masatsuna made considerable reforms in both the military and civilian spheres.

Masatsuna died on 4/8 of Tenshō 2 (1574).  At the Honkō Temple, the date of 3/13 of Tenshō 7 (1579) (the one-year anniversary of the death of Uesugi Keshin) is inscribed on his gravestone.  There is a story, in his last will, he requested this be inscribed on his grave as a means to demonstrate his willpower to outlive Kenshin as his worthy rival.


From an early age, Masatsuna was known as being very bright and courageous.  After maturing, he excelled in military strategy and was skilled in the art of the spear.  He was also known as merciful and compassionate toward citizens, maintaining peaceful relations with neighboring daimyō.  He respected the family of the deputy shōgun of the Kantō (Uesugi Kenshin) and expressed his pure will.

Among the hereditary heads of the Sano clan, Masatsuna is the only one who has a portrait.  This was made in 1579 by Kanō Shōei and inscribed by a monk and diplomat named Sakugen Shūryō and is kept at the Taian Temple in the city of Sano in Ibaraki Prefecture.