From the wiki: “Aburatsubo (‘Oil Vase’) is an inlet on the west side of the Miura Peninsula in Kanagawa, Japan, facing Sagami Bay on the Pacific Ocean. It exits into neighbouring Moroiso inlet.
“According to legend the name, Aburatsubo, comes from the time when hundreds of samurai, fleeing the troops of Hōjō, drowned in the waters of the inlet and left it a sea of blood. However, the inlet has historically been a ‘hurricane hole’ where fishing boats from the area take refuge when a typhoon arrives. The calm, protected waters of the inlet suggest they are the actual reason behind the name ‘Aburatsubo’ (ref. ‘pouring oil on troubled waters’).
“During historic times, the Aburatsubo inlet was selected by the feudal Miura family to build a series of fortifications, with Arai castle at its center. During the Sengoku period, the castle fell after a 3-year siege to the rival Late Hōjō clan, in the year 1516. The Hōjō later managed to unify most of the Kantō.”