Just to clarify - nothing we have discussed is actually 'free castling'. In free castling, the king can choose which square and the rook also has a choice of which square.
Ah OK, I was confusing free castling wih flexible castling. Indeed free castling is still a problem. I guess explicitly wriing the Rook move is the most logical solution there. Like K~b1,Re1. At the moment the interactive diagram doesn't support this type of castiling at all. (In the AI, that is; as far as the user interface is concerned you can enter any double move, as there is no enforcement of turn order.)
Hello HG, When castling short, the king can go on top of the rook, but it should not.
This could be an artifact of the old way the diagram worked, (from before I introduced a j modifier on O) where it always allowed castling with a piece that moved as a Rook, no matter where it was located. The O4 castling in your case specifies the Cannon, as it doesn't have a j prefix. But only the AI respects that. When you alter the move of R to mRcR, does it still highlight the Rook?
Ah OK, I was confusing free castling wih flexible castling. Indeed free castling is still a problem. I guess explicitly wriing the Rook move is the most logical solution there. Like K~b1,Re1. At the moment the interactive diagram doesn't support this type of castiling at all. (In the AI, that is; as far as the user interface is concerned you can enter any double move, as there is no enforcement of turn order.)
This could be an artifact of the old way the diagram worked, (from before I introduced a j modifier on O) where it always allowed castling with a piece that moved as a Rook, no matter where it was located. The O4 castling in your case specifies the Cannon, as it doesn't have a j prefix. But only the AI respects that. When you alter the move of R to mRcR, does it still highlight the Rook?