The symmetrical try 1. e4 f5 2. exf5=S? fails, because the third white knight cannot be explained by promotion at f8. Under the new interpretation, the intended solution also fails, because promotion on d8 would have disrupted Black castling rights.
The symmetrical try 1. e4 f5 2. exf5=S? fails, because the third white knight cannot be explained by promotion at f8. Under the new interpretation, the intended solution also fails, because promotion on d8 would have disrupted Black castling rights.
