Chengyu are mostly derived from
ancient literature, including the pre-Qin classics, poetry from all periods of Chinese history, and late imperial vernacular novels and short stories. A small number were constructed in the 19th and early 20th centuries from Western source materials. Among the early classical literature, the lyrical imagery from the
Classic of Poetry, and the detailed stories recorded in the
Zuo Zhuan and the
Records of the Grand Historian serve as particularly rich source materials for chengyu. Since the
Shijing poems consist of four-character lines, some
chengyu are direct quotes from the
Classic of Poetry. For example, 'ten-thousand year lifespan without bound', a traditional expression to wish someone a long life that often appears on bowls and tableware, quotes the poem "Tian Bao" (, poem #166) in the Lesser Court Hymns section of the
Classic of Poetry. More commonly, however,
chengyu are created by succinctly paraphrasing or summarizing the original text, usually by selecting the most salient characters from the passage in question and inserting any necessary classical grammatical particles. As such,
chengyu are fossilized expressions that use the vocabulary and follow the syntactic rules of
Literary Chinese. Consequently, they convey information more compactly than normal vernacular speech or writing. They may contain subject and predicate and act as an independent clause (or even twin two-character independent clauses in parallel), or they may play the role of any part of speech in a sentence, acting syntactically as an adjective, adverb, verb, or noun phrase. In both speech and writing, they serve to succinctly convey a complex or multifaceted situation, scene, or concept, and used fittingly and elegantly, they also mark a speaker or writer's erudition. The meaning of a
chengyu usually surpasses the sum of the meanings carried by the four characters, as
chengyu are generally meant to convey the message or moral of the myth, story or historical event from which they were derived. Thus, even after translation into modern words and syntax,
chengyu in isolation are often unintelligible without additional explanation. Since they often contain a classical allusion, known as a (), elementary and secondary school students in greater China learn
chengyu as part of the classical curriculum in order to study the context from which the
chengyu was born. Often the four characters reflect the moral behind the story rather than the story itself. For example, the phrase "" ('''', lit: "break the pots and sink the ships") is based on a historical account where the general
Xiang Yu ordered his troops to destroy all
cooking utensils and boats after crossing a river into the enemy's territory. He won the battle because of this "no-retreat" strategy. Thus, the idiom is used as a verb phrase with the meaning "to make an all-out effort to achieve success by the deliberate removal of recourse or backup." Similar phrases are known in the West, such as "Burning one's boats", "burning one's bridges", "
Point of no return" or "
Crossing the Rubicon". Another example is ('''' 'melon field, beneath the plums'), whose meaning relates to the appearance of misconduct or impropriety. It is derived from an excerpt of a
Han-era poem (,
Yuèfǔ Shī "
Jūnzǐ Xíng"). The poem includes the lines 'don't adjust your shoes in a melon field, and don't tidy your hat under the plum trees' (, ''''), admonishing the reader to avoid situations where, however innocent, he might be suspected of doing wrong. The idiom is impossible to understand without the background knowledge of the origin of the phrase. Some idioms have had their literal meanings overtake their original ones. For example, 'wind from an empty cave' (,
kōng xué lái fēng), despite now being used to describe rumors without source, originally referred to rumors with actual, solid sources or reasons. Likewise, 'bare-faced facing the emperor' () is now used to describe beauty that does not require make-up, e.g., when entering court, while its original meaning was "to be confident in one's true look". However, not all
chengyu have stories to draw morals from. An example is 'speaking, yet without trust', referring to one who cannot be trusted despite what he says, an essentially deceitful person. It is generally acknowledged as a
chengyu as it comes from the
Analects. The idiom is succinct in its original meaning and would likely be intelligible to anyone learned in formal written Chinese, though () is no longer commonly used as a verb. There are a few
chengyu that are not four characters in length. An example is the seven-character 'The Old Drunkard's attention is not directed towards his wine'. This is a direct quote from
Ouyang Xiu's essay ''An Account of Old Drunkard's Pavilion'' (), in which the author, as the Old Drunkard, expresses his true intention of enjoying the scenery of the mountains and rivers as he drinks. As an idiom, it expresses the situation where one does something with an ulterior though benign motive in mind. Some
chengyu have English equivalents. For example, 'speak not from the bosom' and 'to speak with one's tongue in one's cheek' share idiomatic meanings. The Chinese not having conducted maritime explorations of the North Atlantic during imperial times, the expression 'one corner of an ice mountain' is a rare example of a
chengyu that emerged in the early 20th century after contact with the West as a translation of the expression "tip of the iceberg," thus sharing both their literal and idiomatic meanings. Another expression 'extracting chestnuts from the fire', originating from a
La Fontaine fable, means "to be duped into taking risks for someone else," used in much the same way as the expression "cat's paw" in English is another example of an "international"
chengyu. Though they are recent in origin, they are constructed using the vocabulary and syntax of Literary Chinese and fits within the four-character scheme, making them
chengyu. Chinese idioms can also serve as a guide through Chinese culture.
Chengyu teach about motifs that were previously common in Chinese literature and culture. For example, idioms with nature motifse.g., mountains, water, and the Moonare numerous. Works considered masterpieces of Chinese literaturesuch as the
Four Great Classical Novels – serve as the source for many idioms, which in turn condense and retell the story. All Chinese people know idioms, though the total number known by any one individual will depend on their background. Idioms are such an important part of Chinese popular culture that there is a game called 'connect the chengyu' that involves someone calling out an idiom, with someone else then being supposed to think of another idiom to link up with the first one, so that the last character of the first idiom is the same as the first character of the second idiom, and so forth. ==Chinese examples==