Grand Admiral a naval rank in one of the highest in the several European navies that use this system, what system are they using?
Military rank Military ranks are a system of hierarchical relationships in armed forces, police, intelligence agencies or other institutions organized along military lines. Usually, uniforms denote the bearer's rank by particular insignia affixed to the uniforms. Ranking systems have been known for most of military history to be advantageous for military operations, in particular with regards to logistics, command, and coordination; as time went on and military operations became larger and more complex, military ranks increased and ranking systems themselves became more complex.
Chief of Naval Operations (South Korea) The Chief of Naval Operations of the Republic of Korea (Korean: 대한민국 해군참모총장 , Hanja: 大韓民國海軍參謀總長 ), shorten as CNO, is the professional head of the Republic of Korea Navy (ROKN) since its foundation in 1948, originally held by a vice admiral, then by an admiral since 1968.