Siege of Musashi-Matsuyama
1537 CE.
Shown on the map at 36.038°, 139.421°.
The 1537 siege of Musashi-Matsuyama was the first of several sieges of Matsuyama castle in Japan's Musashi province over the course of the Sengoku period (1467-1603). The Uesugi clan controlled the castle in 1537, but lost it to the Hōjō clan in this siege; they would regain it, and lose it once more in 1563. The Uesugi sent for help during this siege by hiding a message inside a dog's collar; the tactic was ultimately unsuccessful.
Text from the Wikipedia article Siege of Musashi-Matsuyama (1537), licensed CC BY-SA 4.0.