(佐久間 盛政, 1554
- July 1
) was the son of Sakuma Moritsugu, cousin of Sakuma Nobumori, a prominent Oda retainer to Oda Nobuhide
and Oda Nobunaga
. He was a retainer of Shibata Katsuie
and one of his top generals in many of his campaigns. Morimasa was given the former Ikko Sect fortress Oyama Gobo in the Kaga prefecture by Oda Nobunaga; the fortress was subsequently named Oyama Castle in 1580 but went on to become Kanazawa Castle. After several campaigns in which he had fought, he was given the nickname onigenba
which literally means "Demon Genba", Genba being his middle name. After the betrayal of Akechi Mitsuhide
, Morimasa sided with Shibata Katsuie
over making Oda Nobutaka the heir to the Oda clan while Hashiba Hideyoshi (later Toyotomi Hideyoshi
) supporting Lord Sanboshi, heir to Oda Nobutada but nevertheless, a child. This argument led to the split of the Oda clan retainers with the main factions led by Shibata Katsuie and Hashiba Hideyoshi. In 1583, Morimasa led an offensive against Takayama Ukon in Iwasakiyama. Morimasa then proceeded against Shibata Katsuie's orders and defeated Nakagawa Kiyohide
at the battle of Shizugatake
in 1583, further ignored orders by Shibata Katsuie to fall back led to his defeat as Toyotomi Hideyoshi
's forces approached the next morning. Morimasa continually ignored the orders to retreat and did not abandon his position where he engaged the enemy. Despite calls for reinforcements he was subsequently defeated. Morimasa then attempted to flee, but was captured and beheaded.
The charge by Morimasa was the spark necessary for the battle of Shizugatake where Hideyoshi's troops were able to suppress any resistance led by Maeda Toshiie and prevented the support of Sassa Narimasa and Takigawa Kazumasu. In all, Hideyoshi's troops swelled to 120,000 whereas Shibata Katsuie's troops had only reached 25,000. This eventually forced Shibata Katsuie to commit seppuku along with his wife Oichi following the betrayal of Maeda Toshiie.