learned fool; scholar who cannot apply what he or she knows; mere scholar

(lit. one eye, two legs/feet, three courage, four power) "first, eyes, second, feet, third, courage, fourth, power". The essentials of [kendo] in descending order of importance

Traditional Chinese (Chinese written using traditional characters)

Simplified Chinese (Chinese written using simplified characters)

(literally) know the other side and yourself, a hundred battles will not be perilous