know sth like the back of one's hand

125 useful English phrases for every day use

know something like the back of your hand means “know something[a place] very, very well”

무언가를 훤히 알다, 무언가를 속속들이 알다, 무언가를 구석구석까지 잘 알다

Example: If you get lost, just ask me for directions. I know this part of town like the back

of my hand.