Deep knowledge is to be aware of disturbance before disturbance to be aware of danger before danger to be aware of destruction before destruction to be aware of calamity before calamity.
... By Deep Knowledge of principle one can change disturbance into order change danger into safety change destruction into survival change calamity into fortune. i
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Invincibility is a matter of defense vulnerability is a matter of attack. ... Invincibility is in oneself vulnerability is in the opponent. ii