Grimshaw in fairy problem 2

1.Bf8! th. 2.Re2#
1...Re3 2.Qd2#
1...Qe3 2.Re8#
1...Be4+ 2.Rg6#
1...Rge4 2.Qe5#

Intelligent use of fairy condition allows Grimshaw at e3 (not e4) and two other interferences with Re1 at e4.

1.Bc1! th. 2.Qd4#
1...Bd4 2.Qf5#
1...Rd4 2.Qf3#
1...e1~ 2.Bc4#
1...Rb6 2.Qd6#

Defence motive of black Grimshaw moves to d4 (threat square) is white selfcheck preventing mate by Circe self-protecting queen. But by standard interference they allow other mates by self-protecting queen. And in by-variations there are two other mates by self-protecting white pieces. Together 5 such mates.

a) 1.Bxf2 Ke1! 2.Sc5 Sxf2 3.Be4 Sg4#

b) 1.Rxf2 Kg2! 2.Sf6 Sxf2 3.Re4 Sxd3#

To allow mate by white knight, Black must first capture one and then move own knight far enough. This reveals guard on mating square as well as unblocks e4 and finally desired Grimshaw comes into action. But wait! If black started by wrong capture et f2, white wouldn't have safe tempo move. That determines movements in both twins.

1.Qg6? zz
1...Rg5 a 2.Bxf6# A
1...Rxg6(Qd1) b 2.Qg1# B
1...Bg5 c 2.Sxf5# C
1...Bxg6(Qd1) d 2.Se2# D
1...Bg8!

1.Qg5! zz
1...Rxg5(Qd1) a 2.Qg1# B
1...Rg6 b 2.Sxf5# C
1...Bxg5(Qd1) c 2.Se2# D
1...Bg6 d 2.Bxf6# A

Marvellous 4-fold Lacny cycle with use of orgue pipes and reciprocal Grimshaw and Nowotny on two squares. Interefering both lines to f6 and f5 allow mates on these squares, captures of queen result in mates using reborn queen. Captures by rook pins Sg3, captures by bishops prevent Qg1# by threat of capture of pawn on f-file.

1.a8B+!
1...Rc6 2.Rh6+ Be4 3.Bg6#
1...Be4 2.Bh7+ Rc6 3.Rg6#

"All in Chess" is very strange condition. It allows both sides to move by pieces of both colours, with only one exception - the immediate return of position is not allowed. Thus we can see the mechanism. The check by Ba8 (that cannot be moved away by Black) forces Black to interfere - at c6 by rook or at e4 by bishop. But White immediately moves interefering piece away, in fact critically, behind g6. That leaves Black with only remaining defence, the one not used in 1st move, and white mates by interefering at g6. Standard Grimshaw, but executed by white!