Go Rin No Sho : A Book

My Way of strategy is the sure method to win when fighting for your life one man against five or ten. There is nothing wrong with the principle "one man can beat ten, so a thousand men can beat ten thousand". You must research this. Of course you cannot assemble a thousand or ten thousand men for everyday training. But you can become a master of strategy by training alone with a sword, so that you can understand the enemy's stratagems, his strength and resources, and come to appreciate how to apply strategy to beat ten thousand enemies.