A 'coiled snake' possesses enormous potential energy but provides zero data to the observer. Until it strikes or uncoils, its true 'length' (its full reach or ultimate capability) remains a mystery. It teaches that exposing your full power or your complete plans makes you predictable and easily measured. By remaining partially 'coiled' (contained), you maintain the psychological edge over any opponent.
When the snake is coiled, no one knows its true length. The power of the mysterious is its containment. Silence and potential are your greatest strategic weapons.