In his reminiscences "With the Century" Kim Il Sung wrote, "My great-grandfather was a grave keeper for another family, but he ardently loved his country and home town".

The U.S imperialists, who had long sought a chance of aggression on Korea, sent ship General Sherman to Korea in 1866.

When General Sherman sailed up the Taedong River and anchored near Turu Islet, Kim Ung U, together with villagers in Mangyongdae and its vicinity, stretched ropes across the river between Konyu Islet and Mangyong Hill to block the way of the aggressor ship.

When he heard that its crewmen were killing Koreans with cannons and guns and stealing people's possessions at random, he rushed to the walled city of Pyongyang at the head of the villagers and formed a death-defying corps to launch a fire attack on the ship.

He, with the death-defying corps, loaded a lot of small boats with firewood, tied them together, set them on fire and floated them down towards the ship.

The ship was set on fire and sunk.

After the sinking of General Sherman, the U.S. imperialists sent another warship Shenandoah to Korea. He again led people to fight against the aggressor vessel.