The turtle ship is the world’s first iron-clad ship. It was 35m long and had 70 gun holes. It had 10 oars on each side; the deck was clad with iron plates, bristled with sharp spikes so that the enemy could not climb on it. Besides, it had two sails. The smoke and strong smell given out from the dragon-shaped head made it possible to avoid enemy attack or to cover itself.
In the period of the Imjin Patriotic War (1592-1598) when Japan invaded Korea the ships destroyed hundreds of enemy vessels in the battles on the seas off Sachon and Roryang and other sea battles, thereby making a big contribution to victory in the war.