Battle of Shiojiritōge
1548 CE.
Shown on the map at 36.070°, 138.028°.
The 1548 Battle of Shiojiritoge was one of many battles fought by Takeda Shingen in his bid to conquer Japan's Shinano Province.
Text from the Wikipedia article Battle of Shiojiritoge, licensed CC BY-SA 4.0.