Friedrich Chlubna

1.Qd7? th. 2.Se3#
1...Qf3!

1.Bf2? th. 2.Sd6#
1...Sf7!

1.Bb7! th. 2.Qd5+ exd5 3.Bxd5#
1...Sxe4 2.Bf2 th. 3.Sd6# A Sd4 a 3.Se3# B
       2...exf5 3.Qd5#
1...Qxe4 2.Qd7 th. 3.Se3# B Sd4 a 3.Sd6# A
       2...exf5 3.Qd5#

Two logical tries show that White can attack by queen or bishop only after selfpin of black defenders. The threats of tries as well as in variations are precised by the existence of white lines that should not be closed by mating knight. Black defends again by unpin, but this causes selfblock and white can mate by the other move. Thus we see le Grand theme in variations and also twice Palitzsch form of the Dresdner theme. Fine complex.

1.Sf4? th. 2.Sd3#
1...dxc5!

1.Re3? th. 2.Rxe2#
1...exf5!

1.Rg3! th. 2.Rg1#
1...Qxf5+ 2.Rd3+ Qf2 3.Re3 th. 4.Rxe2#
1...Qxc5+ 2.Rc3+ Qf2 3.Sf4 th. 4.Sd3#

Black parries two tries by opening of lines of bRs, by means of pawn capture. White then unpins bQ that defends short threat by two checks. battery checks force bQ's switchbacks and then it turns out that Black has no longer pawn capture at his disposition.

a) 1.Bd8 (Sf8?, Bc8?) Rxg5 2.Se4 Sh3#

b) 1.Sf8 (Bc8?, Bd8?) Bxd5 2.Be5 Rf3#

c) 1.Bc8 (Bd8?, Sf8?) Se7 2.Sf5 Sg6#

Strategy of White is determined by the type of piece at g8. In any case, it should be unpinned by Black in the first move. However, Black must choose his unpinning move carefully, as wrong choice would disallow the following play. Original use of Forsberg twinning.

a) 1.Be7? zz Sf6!

1.Ra6! zz
1...Sxg7 2.Rxg7 S~#
1...Sc7 2.Bxc7 S~#
1...Sf6 2.Rxf6 S~#
1...Sd6 2.Rxd6 S~#

b) 1.Ra6? zz Sd6!

1.Be7! zz
1...Sxg7 2.Qxg7 S~#
1...Sc7 2.Rxc7 S~#
1...Sf6 2.Bxf6 S~#
1...Sd6 2.Bxd6 S~#

First place in WCCT, that say almost everything. Moving the king in twininng changes the move of bS that is in fact double check and thus allows white captures Qxg7, Rxd6, Bxf6 and, a bit surprisingly, unblocking Rgxg7.

1.Qh7! Ra1 2.Qb1+ Rxb1 3.Sg2 Ra1 4.Rd3+ Kc2 5.Se1+ Rxe1 6.Bb1+ Rxb1 7.Rd2+ Kc1 8.Ka2 Ra1#

White has to force Rb1 out of cage as this will allow him to move Ba2 away too and then to enter mating net by wK. To reach this goal he has to sacrifice a lot of pieces. Queen guards second rank, so by the way of manouevre Qh2-h7-b1 he gets rid of her majesty. Then there are 2 switchbacks.

1.Rc8! th. 2.Rc2 dxc2#
1...Bf7 2.Sc6 (Sc4?) Bb3#
1...Bxe8 2.Sc4 (Sc6?) Ba4#
1...Bh5 2.Sf7 g3#
1...Se4 2.Bc5 Sc3#
1...Sf5 2.Be5 Sxe3#

After they key, White line mover on the 8th rank guard all potential mating squares. So when Black defends the threat either by moving bishop away or by closing his line, White closes his own lines (with some additional motives) and thus allows mating.

1.Bb3! th. 2.Bg3#
1...Qa1 2.e3#
1...Rc1 2.e4#
1...Sd7 2.exd3(Pd7)#
1...Sf7 2.exf3(Pf7)#

Moving Bd1 away causes Circe self-guarding of Rg1 and this the threat is created. Black has two pairs of defences. In the first pair, Queen and Rook destroy this selfguarding, but also remove guard of squares on e-file, thus allowing battery mates by wp. In the second pair, Se5 opens bishop line, but blocks rebirth squares of black pawns and thus allow capturing moves of Pe2. Together we see Albino mating moves with fine Circe motivation.

1.Qh8! th. 2.Qxh6 th. 3.Qh2#
1...Sb7 2.Be2+ Bxe2(Bf1) 3.Bxe2(Bc8)#
1...Ba7 2.Bd3+ Rxd3(Bf1) 3.Bxd3(Ra8)#

Repeated battery checks mean mates in the variations. What is interesting in this position - it is the error of black defences against long threat. Black cuts lines aiming at wK (who is placed on perhaps his the most usual square in Circe problems).