The 1550 siege of Fukashi was one of a series of battles waged by Takeda Shingen in his long campaign to conquer Shinano province, which was ruled by a number of minor daimyō, notably the Suwa, Ogasawara, Murakami [ja] and Takato.

Siege of Fukashi
Part of the Sengoku period
Matsumoto Castle, which stands on the site of the earlier Fukashi Castle
Date 1550 Location Fukashi Castle, Nagano Prefecture, Japan 36°14′20″N 137°58′09″E / 36.2388°N 137.9691°E / 36.2388; 137.9691 Result Takeda victory. Ogasawara Nagatoki forced to abandon his lands.
Belligerents
Takeda clan	Ogasawara clan
Commanders and leaders
Takeda Shingen	Ogasawara Nagatoki
Strength
3,200	4,000

Shingen mounted his first invasion of Shinano in 1542 and steadily worked his way northwards, defeating the Suwa and Takato by 1547. His inexorable advance through the province alarmed the Uesugi clan, which controlled Echigo province to the north, and in 1547 Uesugi Norimasa sent an army into the province to confront Shingen, but this was swept aside at Odaihara. At this point the Murakami and Ogasawara finally entered the fray, and Murakami Yoshikiyo succeeded in defeating Shingen at Uedahara (1548), but Shingen regrouped and went back on the offensive in 1550. Identifying Yoshikiyo as the greater threat, he decided to concentrate his initial efforts on the weaker Ogasawara, and attacked their principal castle at Fukashi.

Shingen was able to size Fukashi without much difficulty, and Shingen placed Baba Nobuharu in charge of it the fortress. Matsumoto Castle was later built on the site.^[1]

The loss of Fukashi broke the power of the Ogasawara clan, and Ogasawara Nagatoki was forced to flee and seek refuge with his ally Murakami Yoshikiyo at Katsurao, which was itself besieged by Shingen four years later.^[2]