By means of drum, bell and flag,[7] the direction of large forces in battle is possible, and like unto the direction of small forces.
By the skilful interchange of normal and abnormal manœuvres are the armies certainly preserved from defeat.
The enemy is crushed, like the fall of a grindstone upon an egg, by knowledge of his strength and weakness, and by the employment of truth and artifice.
Moreover, in battle the enemy is engaged with the normal and defeated by the abnormal force.[8]
The abnormal force, skilfully handled, is like the heaven and earth, eternal; as the tides and the flow of rivers, unceasing; like the sun and moon, for ever interchanging; coming and passing, as the seasons.
There are five notes; but by combinations, innumerable harmonies are produced. There are but five colours; but if we mix them, the shades are infinite. There are five tastes, but if we mix them there are more flavours than the palate can distinguish.[9]
In war there are but two forces, the normal and the abnormal; but they are capable of infinite variation. Their mutual interchange is like a wheel, having neither beginning or end. They are a mystery that none can penetrate.
As the rush of rock-shouldering torrents, so is the spirit of the troops.
Like the well-judged flight of the falcon, in a flash crushing its quarry, so should the stroke be timed.