why can’t I do en passant?

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chessvom
when I try to do en passant in does not show it as a legal move
nklristic

Well, you have to show us the example where you tried to play en passant, so we could give you a concrete answer.

StumpyBlitzer

https://support.chess.com/article/683-what-is-en-passant

Just so your aware what it is and when it can be done. 

GeorgeWyhv14

Not all en passant is a legal move. Or the move itself is not legal to be played.

CheesePrix2314

You can't do en passant since you haven't joined r/anarchychess yet

Circumlocutions
Google en passant