了如指掌

liǎorú-zhǐzhǎng
idiom #9,047

Meanings

  1. 1 to know something like the back of one's hand
  2. 2 to know inside out; to have thorough knowledge of

Characters

Literally 'understand as clearly as looking at one's own palm' - you know every line and detail.

Examples

HSK 4
Tā duì zhè zuò chéngshì liǎorú-zhǐzhǎng.
He knows this city like the back of his hand.
HSK 4
Lǎoshī duì měigè xuésheng de qíngkuàng liǎorú-zhǐzhǎng.
The teacher knows each student's situation thoroughly.
HSK 6
Tā duì gōngsī de cáiwù zhuàngkuàng liǎorú-zhǐzhǎng.
She knows the company's financial situation inside out.

Tips

memory
Look at your own palm - you know every line, every crease. That's how well someone knows the subject: 了 (clear) 如 (as) 指掌 (finger-palm).
history
From the ancient text 《论语》. Confucius said that whoever understands the imperial sacrifice would govern the world as easily as looking at their own palm.

Stroke Order

了 le
如 rú
指 zhǐ
掌 zhǎng