Mozi tried hard during the Warring States period
to dissuade states from fighting each other.
He worked for the state of Song
and Lu Ban worked for the state of Chu.
Mozi walked to Chu to defeat Lu Ban in a series of nine war games.
He claimed that he had taught his methods to the soldiers of Song.
This forced the ruler of Chu to cancel his war plan.
See also in The book of science:
Readings on wikipedia: