Where did the phrase it like back of your come from?

The phrase "it's like the back of your hand" is a common idiom, and it's likely a metaphorical expression that developed organically over time. There isn't a specific origin story or historical event that gave rise to this phrase.

Here's why it makes sense:

* Familiarity: The back of your hand is something you see and touch constantly. You know its contours, the lines on it, and its overall shape intimately.

* Knowledge: The phrase implies a level of knowledge and familiarity that is so deep, it's as if you know the subject "like the back of your hand."

Similar Phrases:

* "Know something like the back of your hand"

* "Know something inside and out"

* "Be familiar with something like the back of your hand"

These all point to the same core idea: a deep level of understanding and familiarity.