The life of Xu Yun (Dhamma name: Empty Cloud), nicknamed the last master of Chinese Buddhism (1850-1959).
His brand of Chan Buddhism (called Zen in Japan, Seon in Korea) includes something close to koans called Hua Tou: a short sentence a contemplative has to mull over in order to reach enlightenment. A famous one is: Who were you before you were born? Another: Who is repeating the name of Buddha? Or : Who is dragging this corpse around?
The contemplatives recognize themselves thanks to obscure short conversations. They live among tigers in the mountains, meditate with no movement for 15 days, and die at 119.
His autobiography is available in English here: https://emptycloud.co.uk/articles-2/the-masters-story-年譜/
Two ideas among many:
After reading ten thousand books, walk ten thousand miles.
We become bright by getting rid of old habits. Enduring strife, we realise some degree of enlightenment.