which is which

What particular one is what particular one, or what is the difference between different ones. For example, These twins look so much alike I can't tell which is which, or Both our raincoats are tan; do you know which is which? This idiom was first recorded about 1412.

Common Names:

Name	Pronounced	Usage
Xavior	-	English (Rare)
Si-U	shee-oo	Korean
QuÝ	-	Vietnamese
Yan (2)	-	Chinese
Gisbert	GEES-bert (German)	German, Ancient Germanic
Katrina	[kə'tri:nə]