Korean Turtle Ship

The Korean turtle ship (geobukseon) was an armored oared warship used by Admiral Yi Sun-sin against the Japanese during the Imjin War of 1592 to 1598. It was a modified panokseon with a covered, spiked upper deck to repel boarders, a dragon-head bow, and cannon mounted on multiple sides. Yi deployed turtle ships as shock vessels at engagements including Sacheon (1592) and Hansan-do (1592); his Nanjung Ilgi war diary and the Joseon Veritable Records document them. Korean accounts describe iron spikes; claims of full iron plating remain debated among historians.