The country had even deep-sea fishing fleets.

A Korean history book Samguksagi (Chronicles of the Three Kingdoms--Koguryo, Paekje and Silla) says that whale eyes were presented to the king in 288.

Naval forces of Koguryo repelled seaborne invasions.

The naval forces were strengthened in the period of King Kwanggaetho (391-412) so that they could not only support the ground forces in battles but also conduct independent landing operations.

There are more than 80 historical records about maritime trade of Koguryo.

Koguryo people sailed to Japan and influenced its cultural development.

Their creative activities for making good use of the sea added to the mightiness of the country.