秘诀

secret know-how / key (to longevity) / secret (of happiness) / recipe (for success)

variant of 秘[mi4]

see 秘魯|秘鲁[Bi4 lu3]

secret / secretary

to bid farewell / tricks of the trade / pithy mnemonic formula (e.g. Mao Zedong's 16-character mantra 十六字訣|十六字诀 on guerrilla warfare)