Good old times 11

1...Rxc4 2.Se4+ Rxe4 3.Rc8+ Bc7#
1...bxc4 2.Sb7+ Rxb7 3.f8Q+ Bd6#

1.Qe8! th. 2.Rc8+ Kxd6 3.Be5+ Bxe5#
1...Rxc4 2.Sb7+ Kd5 3.Rd8+ Bd6#
1...bxc4 2.Se4+ Kd5 3.Sc7+ Bxc7#
1...Kxd6 2.Rb6+ Kc5 3.Qc8+ Bc7#
(1...Sxc4 2.Se4+ Kd5 3.Sc7+ Bxc7# or 2.Sb7+ Kd5 3.Sc7+ Bxc7#)

In the set play, after two captures on c4 White exploits possibility of wS capture by bR, thus the choice of checking square. In the solution wQ unguards d6 (important for the threat and nice feature of problem in general - flight-giving key) and also d5 in the masked form (important in two main variations). Then wS after captures on c4 chooses the square where it cannot be captured by bR.

1...Sc4 allows both thematical continuations thanks to block on c4 without any dual avoidance effect (dual). However the coverage of bK nets is very economical.

1.c8S! th. 2.Sxf4+ Kf6 3.Sh5+ Qxh5 4.Sd5+ Ke6 5.Sc7+ Kf6 6.Se8+ Qxe8#
1...Qg2 2.Sc3+ Kf6 3.Sbd5+ Ke6 4.Sc7+ Kf6 5.Sxe4+ Qxe4 6.Se8+ Qxe8#
1...Rh4 2.Sdb6+ Kf6 3.S4d5+ Ke6 4.Sc7+ Kf6 5.Sd7+ Qxd7 6.Se8+ Qxe8#
1...Qf1 2.Sxf4+ Kf6 3.Sfd5+ Ke6 4.Se3+ Kf6 5.Qh8+ Kg6 6.Bf7+ Qxf7#

Rehm mechanism in the pure selfmate form, again with very good white economy - besides thematical trio BSS only queen and a few pawns. Also the placement of black pieces on the board in the sharply determined area is visually attractive. The variation 1...Qf1 starts like the threat, but its finish is very different.

(This s#6 was also placed in FIDE Album 1983-85 as No. 589.)

1.f1R nSe6 2.e1S+ Kxf1(Ra8) 3.d1B Kxe1(Sb8) 4.b2 Kxd1(Bf8) 5.b1Q+ Kd2 6.Qb7 nSd8 7.Be6 Kxd3(pd7) 8.Sc6 Ke4 9.Ra5 nSxb7(Qd8)#

White has no other mating piece available than neutral knight. Hence, it is necessary to build the right cage for the knight and make the final move of white irreversible. There are basically two possibilities (if I am not wrong): either wK captures nS for its rebirth on b8 or g8 in the cage, or nS captures black piece reborn immediately on the square left in the mating move. In the solution the second possibility is right. It is supplemented by black AUW of pieces to be captured and reborn, later making their blockig duties (blocking square for nS or bK).

(This h#9 was also placed in FIDE Album 1983-85 as No. 961.)

a) 1.Kd6 Gb7 2.Kc5 Kb2 3.Kb4 Bb5=

b) 1.Gf6 Gf7 2.Ke5 Bf5 3.Kf4 Gg5=

Quite unexpected pin stalemates even form far echo with translation (0,4) - although it is not exact. Stalemate problems are not as popular as they could be...

1.g1nR e8nS 2.nSc7 bxc7 3.Kb6 Kb4 4.Rng8 hxg8nQ 5.nQa8 b8nB=

One more problem combining features of two previous: 1. AUW in the problem with neutral pieces and 2. helpstalemate stipulation. Two of four promoted pieces are captured in the play: nS is needed to allow np capture from b-file to c-file, while nR has to be removed simply to have stalemate. The final position has some humour as there are in total 9 different moves physically possible by 4 neutral units (PPBQ), but all of them are selfchecks.