burial mound for severed ears
Historical term referring to a mound where severed ears of enemies were buried, most famously associated with the Japanese invasions of Korea (1592–1598).
The Mimizuka in Kyoto originates from Toyotomi Hideyoshi's invasions of Korea.
Compound of 耳 (mimi, 'ear') and 塚 (tsuka, 'mound'). The reading みみづか is a standard rendaku form.