The siege of Shika castle, spanning the years 1546 to 1547, was one of many battles fought in Takeda Shingen's bid to seize control of Shinano Province. Having just defeated Uesugi Norimasa at the battle of Odaihara, Shingen made use of 300 severed heads obtained at that battle to intimidate Shika's garrison. He displayed the heads prominently outside the besieged castle until Kasahara Kiyoshige surrendered.