诀窍
jué qiào · HSK 7
knack
🔑 诀 secret formula + 窍 aperture/opening = the knack, the key that opens it
诀 is a pithy secret formula or trick; 窍 literally means an aperture or hole, and figuratively the crucial opening or insight. Combined, 诀窍 is the knack — the small key bit of know-how that makes something work.