Two long swords inscribed with the poems of Admiral Yi Sun-sin (1545-1598), a distinguished naval commander during the Joseon era, have been designated as national treasures, the Cultural Heritage Administration announced Thursday. The two swords, approximately 2 meters in length and weighing 5 kilograms each, are currently housed within Hyeonchungsa Shrine in Asan, South Chungcheong Province. They are assessed to ha.