Face-to-face: When pieces of opposite colors stand face-to-face with each other on the same file (black piece is on the top of white!), they exchange their roles. A pawn on the first rank cannot move. Any piece can make an en passant capture when it has got a role of Pawn by Face-To-Face.
Breton: When a piece is captured, a piece of the same kind (if there is one) of the capturing side must disappear. If there are several other pieces of the same kind as the captured piece, then only 1 of them must disappear, it is always the capturing side who decides which piece must disappear. If there is no piece of the same kind as the captured piece, then everything happens like an orthodox capture (no piece disappears, except the captured one).
No.1487Pierre Tritten France original – 29.02.2020
white Kf3 Rb3 Bf5 Sa3 Pg7e6g4
black Kd3 Re4 Bc3 Sb8 Sb7 Pc7c6a5
h#2 b) Sa3→b1 (7+8)
Face-To-Face
Breton
a)
1.Sb8-a6 g7-g8=R 2.Sa6-b4 Bf5*e4[-g8] #
b) wSa3-->b1
1.Sb8-d7 g7-g8=B 2.Sd7-f6 Rb3*c3[-g8] # {
(C+ by WinChloe and Popeye 4.83)}
- Interchange of function between white Bishop/white Rook (guard after
change of move provided by black Knight / mate)
- Change of move by black Knight has positive effect for Black (may capture
mating piece) but also negative effects (restore white piece initial move and
annihilate black piece)
- White Pawn promotes only to be annihilated
(Author)
Most spectacular is the fact that the FTF-transformed bSb4/f6 cannot capture the mating piece because Black would have to remove his own Bc3/Re4, re-activating the transformed white piece with self-check.
Most subtle – and to me, most interesting – is the promotion on g8, played only so that White has something other than Rb3/Bf5 (which are needed to guard flights) to remove in the mating move.
Most spectacular is the fact that the FTF-transformed bSb4/f6 cannot capture the mating piece because Black would have to remove his own Bc3/Re4, re-activating the transformed white piece with self-check.
Most subtle – and to me, most interesting – is the promotion on g8, played only so that White has something other than Rb3/Bf5 (which are needed to guard flights) to remove in the mating move.
Checked also by Jacobi. Try in a): 1.Kd2? Rb1 2.Rxe6 [-c6] Sc4+ 3.c7-c5! and in b): 1.Kc4? Rb5 2.Rd4 Sa3+ 3.a5-a4!