Lifespan: Tenbun 18 (1549) to 8/29 of Kanei 9 (1632)
Rank: bushō, daimyō
Title: Junior Fifth Rank (Lower), Governor of Shinano, Governor of Kawachi
Bakufu: Muromachi → Edo
Lord: Ashikaga Yoshiteru → Ashikaga Yoshiaki → Oda Nobunaga → Toyotomi Hideyoshi → Toyotomi Hideyori → Tokugawa Ieyasu → Tokugawa Hidetada
Father: Kutsuki Harutsuna
Mother: Daughter of Asukai Masatsuna
Wife: [Formal] Daughter of Gyōe (a monk of the Jōdo sect)
Children: Nobutsuna, Tomotsuna, Tanetsuna, daughter (wife of Hori Naomasa)
Kutsuki Mototsuna served as a bushō and daimyō during the Sengoku and Azuchi-Momoyama periods and as a yoriai–hatamoto during the early Edo period.
Mototsuna was born as the son of Kutsuki Harutsuna and the daughter of Asukai Masatsuna.
In 1550, his father, Harutsuna, was killed in action, so Mototsuna inherited the headship of the clan at the age of two. From 1553, Ashikaga Yoshiteru, the thirteenth shōgun of the Muromachi bakufu ousted from Kyōto by Miyoshi Nagayoshi, sheltered with him in Kutsukidani in Ōmi Province as he had with Mototsuna’s father. In 1566, following an invasion of the Takashima District by Azai Nagamasa, Mototsuna tendered a hostage. In the twelfth month of 1568, he exchanged a written pledge with Nagamasa and Azai Hisamasa (Nagamasa’s father) but, before long, this was breached.
In 1570, during an invasion by the Asakura clan, Matsunaga Hisahide persuaded Mototsuna to assist Oda Nobunaga in withdrawing from Kyōto on the Kutsuki Ridge. Later, Mototsuna served Nobunaga and, under the command of Nobunaga, he was first assigned to Isono Kazumasa. After the ouster of Kazumasa, he served under Tsuda Nobuzumi. In 1579, Mototsuna was dismissed from his role as a magistrate so did not appear to have been well-supported by Nobunaga.
After the demise of Nobunaga in 1582, Mototsuna served Toyotomi Hideyoshi and was appointed as the magistrate of landholdings under the direct control of the Toyotomi in the Anō District of Ise and the Takashima District of Ōmi. He also participated in the Conquest of Odawara. In 1595, Hideyoshi recognized his rights to 9,203 koku in the Takashima District.
In 1590, he was conferred the Toyotomi surname by Hideyoshi.
In 1600, at the Battle of Sekigahara, initially, he followed Ōtani Yoshitsugu as a member of the Western Army, but, acting in concert with Kobayakawa Hideaki, he joined Wakizaka Yasuharu, Ogawa Suketada, and Akaza Naoyasu to switch sides to the Eastern Army. It is surmised that he did not make clear his collusion so his fief was reduced from 20,000 koku to 9,590 koku. However, as noted, the value of his fief earlier recognized by Hideyoshi barely changed so it appears that he did in fact collude in advance and his territory was recognized after the war by Tokugawa Ieyasu. Finally, there is a theory that Mototsuna did not participate in the Battle of Sekigahara.
In 1616, he underwent the rites of tonsure and adopted the monk’s name of Bokusai. In 1632, he died in Kutsukidani at the age of eighty-four.
After his demise, his landholdings were divided among his three sons so the main branch of the Kutsuki retained 6,300 koku. Later, the youngest child, Tanetsugu, earned the trust of the third shōgun of the Edo bakufu, Tokugawa Iemitsu, and was elevated to the position of a daimyō so members of the illegitimate branch gained more landholdings than the main branch of the Kutsuki family.