Lifespan: Unknown to 1/22 of Tenbun 20 (1551)
Other Names: Tarō
Rank: sengoku daimyō
Title: Master of the Office of Palace Repairs, Governor of Iki
Father: Nasu Masasuke
Mother: Daughter of Iwaki Tsunetaka
Siblings: Takasuke, Suketane, Sukekuni
Wife: Eldest sister of Nantai Myōkō (daughter of the Haga clan)
Adopted Children: Sukeie (second son of Satake Yoshiaki)
Nasu Takasuke served as a sengoku daimyō of Shimotsuke Province during the Sengoku period. Takasuke was the nineteenth head of the Nasu clan.
Takasuke was born as the eldest son and lineal heir of Nasu Masasuke, the eighteenth head of the Nasu clan. He received one of the characters from the name of Ashikaga Takamoto, the third-generation Koga kubō, and adopted the name of Takasuke.
Beginning from 1509, internal conflicts in the family of the Koga kubō and the Eishō Disturbance exerted an influence on the clans in Shimotsuke. Within the Nasu clan, Ōzeki Munemasu backed Takasuke, coming into conflict with Takasuke’s father, Masasuke. To oppose his father who joined forces with Utsunomiya Hisatsuna, along with Satake Yoshiatsu and Oda Masaharu of Hitachi Province, Takasuke allied with the Iwaki clan of southern Mutsu Province, in addition to Yūki Harutsuna, Yūki Masakatsu of Shimōsa Province, and Masakatsu’s next younger brother, Oyama Takatomo from Shimotsuke.
On 9/21 of Tenbun 8 (1539), Takasuke incurred an attack at Karasuyama Castle by Masasuke supported by Utsunomiya Hisatsuna and reinforcements from Satake Yoshiatsu and Oda Masaharu. In 1542, Ōzeki Munemasu was attacked by Ōtawara Sukekiyo. Around 1544, Takasuke appears to have formally received the headship of the clan from his father. Known for a strong sense of independence among its members, Takasuke attempted to strengthen control over the clan but failed.
On 9/17 of Tenbun 18 (1549), Takasuke led 300 soldiers to invade the territory of the Utsunomiya. As a result, upon orders from Ashikaga Haruuji, the fourth Koga kubō, Utsunomiya Hisatsuna led an army of 2,500 men to deploy to the Kitsure River and engage in battle against the Nasu forces. This is known as the Battle of Kitsuregawa-Sōtomezaka.
Initially, the Utsunomiya enjoyed an advantage based on their superior numbers, so Takasuke used troops lying in ambush in Sōtomezaka to create havoc for the Utsunomiya army, reversing the tide of the battle in favor of the Nasu. Takō Nagatomo (a retainer of the Utsunomiya), Michikawa Tadachika (a retainer of the Kasama), and the Yokota brothers (five sons of Yokota Tsunamura who were retainers of the Yokota) fought valiantly, halting the assault by the Nasu army, but Tadachika and the Yokota brothers were killed in action. These individuals are known as the Five Brothers of the Yokota. In an effort to control his army amidst the chaos, Hisatsuna went to the front lines of the battle but died after being struck in the chest by an arrow shot by Ayugase Sanemitsu, a retainer of Iono Sukenobu. The battle ended in victory for the Nasu army led by Takasuke. Owing to the ensuing disarray in the Utsunomiya clan, the Nasu were able to expand their territory into a portion of the Shioya District.
In 1551, Haga Takasada launched a plot to have Senbon Suketoshi, the lord of Senbon Castle in the Haga District, lure and kill Takasuke at the castle as a means to gain retribution for the killing of Hisatsuna in battle. According to one account, he was killed after being served a poisonous Chinese bird. From before, Takasuke had come into conflict with his younger brother of a different mother, Nasu Suketane, over the daughter of Ōtawara Shigekiyo whereupon Takasuke pressured and finally ousted Suketane, promoting her adoption and marriage to the son of Satake Yoshiaki. After the death of Takasuke, Suketane inherited the headship of the clan and then relied upon Senbon Suketoshi as a close associate and the unexpected death of Takasuke conformed to the will of the Upper Nasu group (comprised of the Ōzeki and Senbon clans) led by Sukekiyo.