The characters literally combine to mean: “According to the picture, search for the thoroughbred horse.” The meaning comes directly from the story of its origin.
The idiom originates from a story set in ancient China's Spring and Autumn period. A man named Sun Yang, better known by his courtesy name Bo Le (伯乐), was a legendary judge of horses. He wrote a book called The Canon of Horses (《相马经》, Xiàng Mǎ Jīng), detailing how to identify a fine steed. His son, believing he had mastered the book, took it and went out to find a thoroughbred. He followed the descriptions so literally—“a high forehead, bulging eyes, and hooves like stacked blocks of ginger”—that he came back triumphantly with a large toad, proclaiming he had found a horse that mostly matched the description. This story serves as a classic cautionary tale against dogmatism and rote learning, emphasizing that theoretical knowledge is useless without practical wisdom and adaptability. It highlights the cultural value placed on `随机应变 (suí jī yìng biàn)`, or the ability to adapt to circumstances. Compared to the Western phrase “going by the book,” `按图索骥` is far more negative. “Going by the book” can imply diligence, precision, and adherence to proper procedure (a positive trait for an accountant or an engineer). In contrast, `按图索骥` almost always implies foolishness, naivety, and a complete failure to grasp the bigger picture. It's a critique of method, not a praise of thoroughness.
`按图索骥` is frequently used in modern Chinese to criticize an inflexible or unintelligent approach to a problem.
Its connotation is consistently negative and critical. It can range from a lighthearted jab at a friend's clumsy efforts to a serious condemnation of a failed strategy.