刻kè舟zhōu求qiú剑jiàn

Literal: to carve the boat in order to find the sword
Figurative: Clinging to a rigid method while ignoring that circumstances have changed; stubborn inflexibility in the face of a situation that has already moved on.

Where does 刻舟求剑 come from?

A man of the state of Chu was crossing a river by boat when his sword slipped into the water. Instead of diving in at once, he cut a notch on the side of the boat at the spot where the sword had fallen, saying, "This is where my sword went over." When the boat reached the shore, he got into the water at the notch to look for it. But the boat had moved and the sword had not, so of course he never found it.

Source (出处): 《吕氏春秋》

How is 刻舟求剑 used? Two examples

市shì场chǎng早zǎo就jiù变biàn了le，你nǐ还hái用yòng十shí年nián前qián的de老lǎo办bàn法fǎ，简jiǎn直zhí是shì刻kè舟zhōu求qiú剑jiàn。
The market changed long ago, yet you still use the old methods of ten years back; it is simply carving the boat to find the sword.
情qíng况kuàng已yǐ经jīng不bù同tóng了le，照zhào搬bān旧jiù规guī定dìng只zhǐ会huì刻kè舟zhōu求qiú剑jiàn，解jiě决jué不bù了liǎo问wèn题tí。
The situation is already different; mechanically applying the old rules is like carving the boat to find the sword and solves nothing.

In Wanyu, all 400 chengyu have audio on every sentence, and you can save them to your decks and review them with spaced repetition. Free.