Selections 4

a) 1.g1S g8Q 2.Sxe2 Qg1#

b) 1.g1B g8R 2.Bf2 Rg1#

Here it is clear there is no solution in orthodox chess. Even if Black could block enough flights, black promoted piece could always capture back on g1 when White tried the mate on the first rank. So why do two ways of checkmating in Circe and Anticirce work?

In Circe things are easy to understand. Checkmate from g1 means that Black cannot take piece back from e2/f2 as both queen and rook would be reborn on d1/a1. But White has to guard one of squares e2/f2, therefore White promotes to queen, while Black chooses knight.

In Anticirce the idea is slightly more difficult. Clearly, e2 is not flight anymore as Kf8 guards e8 - potential rebirth square of bK. White cannot promote freely to both queen and rook. Check by queen could be parried by bP moving to d1, blocking rebirth square of queen. Thus White chooses rook and Black has to block f2. It is possible by bishop that cannot capture on g1 due to wK blocking f8.

It is quite a good content for AUW h#2 with material KPP-KPP.

a) 1.Kxa4(Sb1) Bxd5(Ra8) 2.Ra5 Sxc3(Bf8)#

b) 1.Kxa4(down Sa4) Bd3 2.Kb3(gSa4) gSc5#

c) 1.Kc4 Sb6+ 2.Kb3 Bxd5(Bd1)#

Again there is no orthodox solution here. But with suitable fairy condition there are wide possibilities. In a) rebirths of both captures in the first moves contribute to the solution (bR can block, wS retain possibility to move to c3). In b) capture and subsequent rebirth of wS makes it invulnerable so that knight can mate on well guarded c5. In c) the capture of bR on mating moves makes possible placement of wB further from Kb3 on d1-a4 diagonal. However, black play is not very interesting.

a) 1.Rb7 Bd3 2.Ra7 f1B 3.g8B+ g1B#

b) 1.Qa7 Ba6 2.Rb8 f1Q 3.g8Q+ g1Q#

The primary aim of White is to force promotion move of Pg2, opening lethal battery to wK. Two conditions with paralysis can motivate that by forcing specified promotion. The checkmate is not given by original Bf1 as it has to do line closing duties during solution, so that Black has to replace it.

In a) bishop promotions are motivated as follows. Queen on f1 could be paralysed in W4, thus 2...f1B. 3.g8B+ ties black Sh6 so that it cannot prevent check from Ra7 by 3...Sf7?? And finally 3....g1B# must paralyze Ra7.

In b) queen promotions are slightly different. Bishop on f1 could be paralyzed in W4, thus 2...f1Q. 3.g8Q+ is necessary to give double check that can only by parried by 3...g8Q#.

a) 1.Kg8! th. 2.Bh6#
1...Qh3 a 2.Rxd4# A
1...Rc8 b 2.Qd6# B

b) 1.Kg8! th. 2.Bh6#
1...Qh3 a 2.Qd6# B
1...Rc8 b 2.Rxd4# A

Reciprocal change of mates is understandable in this direct twomover. While in orthodox a) both black defences are simple unguards, in Madrasi b) the strategy of black errors is slightly more complicated. Both checks Rxd4# and Qd6# are not guarded by Q and R respectively due to opening of paralysis lines, but they can be parried by paralyses Rd6 and Qb4. Thus defences remove these possibilities.

a)
1.Qf5 Sa7 2.Qxb5 Sxb5#
1.Rc2 Sb6 2.Rxc4 Sxc4#

b)
1.f5 g6 2.Bd8 Kxe2#
1.b6 e5 2.Ba8 Kxf2#

Quite unusual fairy HOTF helpmate. Orthodox solutions are easy to understand - black pieces Qf2/Re2 allow checkmating moves by capturing the blocking pawns.But Mars Circe is such weird fairy condition that makes it hard to believe that the same position can be solved twice in analogous manner too under this condition. Let's see.

Any move of wK unblocks b1, thus allowing check from Sc8. Pb2 cannot block b1 due to Pb5. Sc8 is the only piece that can check, it even need not to move. However Re2 and Qf2 could capture it from a8 and d8. Hence both R and Q have to be eliminated somehow as there is not enough time for jumping away from c8 to other white square and move by wK. One of piece is neutralized by block of the Circe square by bishop and the other is captured by battery piece, wK.

a) 1.Be4! th. 2.Sd3+ A Kc6 3.Se5#
1...d3 a 2.Sc2+ B Kc6 3.Sd4#

b) 1.Kd7! th. 2.Sxc2+ B Kxd5 3.Sxe3#
1...Bxd3 a 2.Sxd3+ A Kxd5 3.Rxd6#

The differentiation of play is based on key difference between Andernach and Antiandernach chess: in a) White wants to make only non-capturing moves, while in b) he prefers capturing moves. That is why in a) wB must in a key unblock d3 and Black defends by entering the square (at the same time frees c2). In b) then White uses the other potential Siers flight d5 as this allows capturing checkmate Sxd3. Interesting version of the change of conditions.