Starship Girl Yamamoto Yohko

In a thousand years from now, the great battles between civilizations have been reduced to the shoulders of a handful of chosen champions. When a war is waged, each side picks its representatives, gives them spaceships, and the fight is on! Of course, if their champion loses, they must admit defeat and give in to the wishes of the other. Very handy, very civilized ... unless you don't happen to have any good fighters...