Four-character idioms are widely used in Chinese language as chéng yǔ (成語, literally "to become (part of) the language"). Chéng yǔ are mostly quotes from ancient literature. Many of these idioms carry meanings much more than the sum of the four characters. When students in China learn chéng yǔ in school, they need to study the stories behind the phrases. Often the four characters are just a hint to the moral behind those stories. For example, the phrase "破釜沉舟" (pò fǔ chén zhōu) literally means "crack the woks and sink the boats." It was based on a historical account where a general ordered his troop 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" policy. The phrase is used when one succeeds by burning the bridge. This particular idiom is never used in a losing scenario because the story behind it does not describe a failure.

The following three examples show that the meaning of the idiom can be totally different by only changing one character.

• 一日千秋 (yī rì qiān qiū)
  • Literal: One day, a thousand autumns.
  • Usage/Moral: implies rapid changes; one day equals a thousand years

• 一日千里 (yī rì qiān lǐ)
  • Literal: One day, a thousand miles.
  • Usage/Moral: implies rapid progress; traveling a thousand miles in a day

• 一日三秋 (yī rì sān qiū)
  • Literal: One day, three autumns.
  • Usage/Moral: greatly missing someone; one day feels as long as three years

• 傍若無人 (bō jaku bu jin)
  • Literal: As if there is nobody beside (you).
  • Usage/Moral: One has a very high opinion of self and acts any way s/he wants.
  • Source: The Biography of Xiè Shàng (謝尚), Volume 79, the Chronicle of Jìn.

• 起承転結 (ki shō ten ketsu)
  • Literal: Start, Continue, Change, Conclusion
  • Usage/Moral: This is the most popular story style in Japan.
  • Source: