了若指掌 liǎo ruò zhǐ zhǎng like the back of one's hand

Explanation

形容对事物了解得非常清楚，就像把东西放在手掌里给人看一样。

It describes understanding something very clearly and thoroughly, as if presenting it in one's palm.

Origin Story

话说唐朝时期，有个名叫李白的才子，他博览群书，对诗词歌赋以及历史典故都了若指掌。一日，皇帝召见李白，问及一些比较冷门的历史事件，李白对答如流，令皇帝赞叹不已。他如同将历史的点点滴滴都握于掌中，清晰明了，精准无误。此事传扬开来，人们都敬佩李白的才学和渊博的知识。

huà shuō táng cháo shíqī, yǒu gè míng jiào lǐ bái de cáizǐ, tā bólǎn qún shū, duì shī cí gē fù yǐ jí lìshǐ diǎn gù dōu liǎo ruò zhǐ zhǎng. yī rì, huángdì zhào jiàn lǐ bái, wèn jí yī xiē bǐjiào lěng mén de lìshǐ shìjiàn, lǐ bái duì dá rú liú, lìng huángdì zàntàn bù yǐ. tā rútóng jiāng lìshǐ de diǎn diǎn dī dī dōu wò yú zhǎng zhōng, qīngxī míngliǎo, jīngzhǔn wú wù. cǐ shì chuányáng kāilái, rénmen dōu jìngpèi lǐ bái de cáixué hé yuānbó de zhīshi.

In the Tang Dynasty, there was a great scholar named Li Bai, who had vast knowledge of Chinese literature, classical poems, and historical events. One day, the Emperor summoned Li Bai and asked him about some obscure historical details. Li Bai answered fluently and accurately. The Emperor was full of admiration. It is said that he held these details so firmly in his mind that they felt as if they were in the palm of his hand. This story spread widely, and people admired Li Bai's extraordinary scholarship.

Usage

常用来形容对某事物的了解非常透彻，掌握得非常熟练。

cháng yòng lái xíngróng duì mǒu shìwù de liǎojiě fēicháng tòuchè, zhǎngwò de fēicháng shúliàn

Often used to describe a thorough and proficient understanding of something.

Examples

• 他对公司的情况了若指掌。

  tā duì gōngsī de qíngkuàng liǎo ruò zhǐ zhǎng

  He knows the company's situation like the back of his hand.

• 他将最新的市场信息了若指掌。

  tā jiāng zuìxīn de shìchǎng xìnxī liǎo ruò zhǐ zhǎng

  He has a comprehensive grasp of the latest market information.

Related Idioms

• 了如指掌

• 熟知

Opposite Idioms

• 一窍不通

• 茫然无知