The Republic of China Navy is the maritime branch of the Republic of China Armed Forces. The ROC Navy's primary mission is to defend ROC territories and the sea lanes that surround Taiwan against a blockade, attack, or possible invasion by the People's Liberation Army Navy of the People's Republic of China. Operations include maritime patrols in the Taiwan Strait and surrounding waters, as well as counter-strike and counter-invasion operations during wartime. The Republic of China Marine Corps functions as a branch of the Navy.
The ship prefix for ROCN combatants is ROCS (Republic of China Ship); an older usage is CNS (Chinese Navy Ship).
ROCN also avoids giving ships hull numbers that add up to or end at "4", as the Chinese pronunciation of the number 4 is close to the pronunciation of "death". This numbering scheme is more apparent on more newly acquired ships.
Note: The ROCN generally uses hull classification symbols similar to the U.S. system with some changes. The proper classification is provided when known.