One general from this region famously used the "crane wing" formation and turtle ships to repel its invading forces.
A group of elite male youth from this region was known as Hwarang, and pirates were suppressed by Jang Bogo in this region. One dynasty in this region signed the Treaty of Kanghwa, and one kingdom in this region gained dominance under king Gwanggaeto the Great, who became the first to unite Goguryeo, Baekje, and Silla. One general from this region famously used the "crane wing" formation and turtle ships to repel its invading forces. For 10 points, name this region once led by the Joseon dynasty, which is currently divided by the demilitarized zone along the 38th parallel.
A group of elite male youth from this region was known as Hwarang, and pirates were suppressed by Jang Bogo in this region.
Korean peninsula [accept Silla before "Gwanggaeto"]