The battle of Dan-no-ura was a major battle of the Genpei war, occurring at Dan-no-ura, in the Shimonoseki Strait off the Southern tip of Honshu in the year 1185. One of the crucial factors that allowed the Minamoto to win the battle was that a Taira general Taguchi Shigeyoshi defected and attacked his Taira Clan from the rear. He also revealed to the Minamoto Clan which ship the 6 year-old Emperor Antoku was on. Their archers turned their attention to the helmsmen and rowers of the emperor's ship as well as the rest of their enemy's fleet, sending their ships out of control. Many of the Taira saw the battle turn against them and committed suicide.
The ema votive is polychromed in rimpa paint on Hinoki wood, framed in black lacquered. The votive is an Edo period commemoration of the 12th century sea battle.