Ensign The flag that indicates nationality on a ship is called an ensign. As with the national flags, there are three varieties: the civil ensign, flown by private owned vessels; state ensigns (also called government ensigns), flown by government ships; and war ensigns (also called naval ensigns), flown by naval vessels. The ensign is flown from an ensign-staff at the stern of the ship, or from a gaff when underway. Both these positions are superior to any other on the ship, even though the masthead is higher. In the absence of a gaff the ensign may be flown from the yardarm. In some countries, the national ensign is identical to the national flag, while in others, such as the United Kingdom and Japan, there are specific ensigns for maritime use. Most countries do not have a separate state ensign, although the United Kingdom is a rare exception, in having a red ensign for civil use, a white ensign as its naval ensign, and a blue ensign for government non-military vessels. Ensigns are usually required to be flown when entering and leaving harbour, when sailing through foreign waters, and when the ship is signalled to do so by a warship. Warships usually fly their ensigns between the morning colours ceremony and sunset when moored or at anchor, at all times when underway, and at all times when engaged in battle.