know (one's) beans

To be knowledgable about and/or very familiar with something. I had no idea you were such a good piano player—you really know your beans!

Name	Pronounced	Usage
Ilene	ie-LEEN	English
Pinchas	-	Hebrew, Biblical Hebrew
Svjetlana	-	Croatian, Serbian
Almast	-	Armenian
Joachim	zho-a-KEEM (French), YO-ah-khim (German), yo-AH-khim (German), yaw-AH-kheem (Polish), JO-ə-kim (English)	French, German, Polish, Judeo-Christian Legend
Bogdan	BAWG-dahn (Polish), BOG-dahn (Serbian, Croatian), bog-DAHN (Romanian)	Polish, Russian, Slovene, Bulgarian, Serbian, Croatian, Macedonian, Romanian, Medieval Slavic