The sieges of Toishi castle (砥石崩れ, Toishi kuzure, "Rout of Toishi") took place during Takeda Shingen's campaign to take over Shinano Province. His army, led by Sanada Yukitaka, began besieging the castle in 1550. The defending lord, Murakami Yoshikiyo, held out until the following year, but his garrison suffered over 1,000 casualties, and was ultimately forced to surrender.

• Turnbull, Stephen (1998). 'The Samurai Sourcebook'. London: Cassell & Co.