Z flag

"Zulu flag". Licensed under CC BY-SA 2.5 via Wikimedia Commons.

Letter "Z" is the last one of the alphabet. There is nothing left after this letter Z. Hoisting this Z flag is a call for full dedication from all people to battles (challenges) ahead.

Z flag - Wikipedia, the free encyclopedia: At the Battle of Tsushima on May 27, 1905, Admiral Tōgō raised a Z flag on his flagship, the Mikasa. By prearrangement, this flag flown alone meant "The fate of the Empire rests on the outcome of this battle. Let each man do his utmost".