조선왕조실록
The first references to older, first-generation turtle ships, known as gwiseon (귀선; 龜船, ), come from 1413 and 1415 records in the "Annals of the Joseon Dynasty", which mention a mock battle between a "gwiseon" and a Japanese warship. However, these early turtle ships soon fell out of use as Korea's naval preparedness decreased during a long period of relative peace.