When I encounter an interesting question on Chess StackExchange, I would like to import that game to http://lichess.org, to be able to analyze it with Stockfish. When I use the "Copy game" option (for example from this question) and paste that PGN into https://lichess.org/paste, it does not work (I get an empty board).
It seems that the problem is the
[FEN ""] tag: if I remove it, it works. If I replace that tag with
[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"], it also works.
Is this a bug in lichess or in stackexchange? In other words, is the empty string a valid FEN position?