ChessFlash

This entry is an example of what can go wrong with your PGN file, what the ChessFlash Viewer does with moves it does not "understand" and how to correct it. Normally, if you are exporting the PGN file from other chess software you should not have any of these issues. These sorts of issues generally occur with hand entered moves or with moves cut-n-pasted off of a web page.

TestData/BadData2.pgn

Press click to play and you will see **(INVALID MOVE: bd2 ) ** [try correcting the error in the pgn file and upload it with a different file name.] ** after move 4. First, what is wrong with bd2? The issue is that the pieces must be specified with an upper case letter. So, "Bd2" would be fine. Also, "Bc1-d2" would work. The PGN specification requires pieces in moves to be represented as upper case characters. Also, note that in the same position Nd2 would not be recognized as a valid move since there are two knights that can be moved to d2 and it needs to be clear which one is intended. To do that you could use "Nbd2". ChessFlash will also recognize "Nb1-d2" or "N1d2".

Another issue to keep in mind is that the destination square must also be fully specified in the move. This is mostly an issue with pawn captures. Use "exd6" or "ed6" but not just "ed".

Ok, so you see what ChessFlash has an issue with and you want to correct it. What do you do? You fix the PGN file and rename it and then re-upload it. If you do not rename it, it may run into internet caching issues and ChessFlash may, for a while, keep trying to use the original unmodified file.

Also notice in the viewer that after the first problem, we seem to have a problem in each of the variations later. In this instance, these are all an artifact of the first error. Since ChessFlash is confused as to the position it thinks the subsequent variations are attempting illegal moves. If the subsequent moves look ok, it is best to just fix the first error and try again.