From Han Yu's (
韩愈) Tang-dynasty essay
《马说》 (Discourse on Horses). Opening:
世有伯乐,然后有千里马。千里马常有,而伯乐不常有 - 'only when a Bole exists can thousand-li horses emerge. Thousand-li horses are common; a Bole is not.' Bole (
伯乐) was the legendary ancient horse-judge; Han Yu uses the horse as an allegory for overlooked human talent.