The tombs are in Sammyo-ri, Kangso County, South Phyongan Province. They are called the three tombs of Kangso as they form a tomb group of big, middle and small tombs of trapezoid shape in a place.

The big one is 50m long and 8.7m high, the middle one 45m long and 7.8m high and the small one about 40m long and 6.75m high.

Each wall of the body chamber of the big tomb was made by piling two to three long and plain rocks, on which parallel and triangular stones were put to form the ceiling. The stones were dovetailed water-tightly.

The tomb showcases the Koguryo people's minute design based on an accurate scientific and technical calculation, skilful construction and delicate stone processing technique.

The murals in the big and middle tombs are excellent out of the remaining tomb murals of Koguryo.

The four guardian deities are the main theme of the murals which are painted on the wall and ceiling stones.

Especially, the blue dragon and the black tortoise-serpent of the big tomb and the white tiger and red phoenix of the middle tomb constitute the acme of Koguryo's pictorial art.

The murals of the Kangso three tombs are appreciated as a masterpiece representing the pictures of the four guardian deities of the Orient in the medieval fine arts circle of the world.