# StrateGems

No. 55, Jul-Sep 2011

R0180 -

StrateGems, No. 55, Jul-Sep 2012

3+4. legal-pser.h#5 (AP)

[3k4/2bpn3/8/8/8/1P6/8/4K2R]

Solution

1.Ba5+ b4 2.Bxb4+ Kf2 3.Bc5+ Ke1 4.Bd6 0-0! (AP) 5.Bc7 Rf8#. Castling cannot play any retro-role, as long as there is a retro-move by the wP. Miniature, Rundlauf (A)

R0181 -

StrateGems, No. 55, Jul-Sep 2012

6+6. legal-pser.h#9, (AP)

[nk6/1p6/3p4/p2b4/2P5/8/P4P1P/R4K2]

Solution

1.Bg2+ Ke1 2.d5 3.dxc4 4.c3 5.c2 6.c1B 7.Be3 8.Ba7 0-0-0! (AP) 9.Sc7 Rd8#. AP (after Keym): Castling AP justifies white's right to move; since, if castling is legal, there is no retro-move for white. According to the AP logic, the side conventionally not on the move (white in helpmates) has the right to seize the turn to move, if it can be proved a posteriori that there was no other retro-move available. White has some retro-moves at first, which disappear afterwards. At any moment we forget the past positions of the solution and analyze only the current one for retro-moves. In any suitable position, white has the right to seize the move, and this is legitimate if and only if it is proved by actual castling. Castling immediately after 3.dxc4 or 4.c3 would be AP-legal as well, but premature!

White puts his King on e1 and waits for an appropriate moment to seize the turn to move, based on AP and castling. Three times, both sides’ turns to move are legal simultaneously; a paradoxical choice that is unusual even for the AP-genre! (A)

R0182 -

StrateGems, No. 55, Jul-Sep 2012

In memoriam Alexander Kislyak

15+11. Check?

[BNk5/BqR1p3/rRQPPPp1/NKpp4/n7/1PP5/1p1P2P1/1n5b]

Solution

Yes, the check is legal. Retract: -1.Rd7xQc7+ h2-h1B -2.Sc4-a5 h3-h2 -3.Se3-c4 h4-h3 -4.Sf5-e3 h5-h4 -5.Sg7-f5 h6-h5 -6.Se8-g7 Qd8-c7 -7.Sc7-e8+ Qh8-d8 -8.f5-f6 Qe5-h8 -9.f4-f5 Qe1-e5 -10.f3-f4 e2-e1Q -11.f2-f3 f3xSe2 -12.Sf4-e2 h7-h6 -13.Sh5-f4 f4-f3 -14.Sf6-h5 f5-f4 -15.Sg8-f6 f6-f5 -16.g7-g8S f7-f6 -17.h6xSg7 Sf5-g7 -18.h5-h6 Se3-f5 -19.h4-h5 Sc2-e3 -20.h3-h4 Sa1-c2 -21.h2-h3 a2-a1S -22.e5-e6 a3-a2 -23.a2xBb3 Bd1-b3 -24.e4-e5 b3-b2 -25.e3-e4 Sb2-a4 -26.c2-c3 Ra4-a6 and everything unlocks. Three Ceriani-Frolkin pieces (bQ, wS and bS).

The position of the white King prevents a bQ from reaching a1 and a bS from being uncaptured on c7, justifying the intermediate white uncapture and unpromotion. The last 22 single moves are completely determined. (A)

R0183 -

StrateGems, No. 55, Jul-Sep 2012

14+12. Check?

[RqR5/Bpb1p3/1KNp4/rN2P1p1/B3n3/PnP2P2/2kPPp2/Q2b4]

Solution

Yes, the check is legal. Retract: -1....Bd8xPc7 -2.a2-a3 Sg3-e4 -3.e4-e5 Sh5-g3 -4.Se5-c6 Sg7-h5 -5.Sg4-e5 Se8-g7 -6.c6-c7 Sc7-e8+ -7.c5-c6 g6-g5 -8.b4xPc5 Sd4-b3 -9.b3-b4+ Sf5-d4 -10.Sh6-g4 Sg3-f5 -11.Sg8-h6 Sh1-g3 -12.Sh6-g8 h2-h1S -13.Sg8-h6 h3-h2 -14.Sh6-g8 h4-h3 -15.Sg8-h6 h5-h4 -16.g7-g8S h7-h5 -17.h6xQg7 Qd4-g7 -18.h5-h6 Qb4-d4 -19.h4-h5 Qa3-b4 -20.h3-h4 Qb2-a3 -21.h2-h3 Qb1-b2 -22.e3-e4 Kc1-c2 -23.Sa3(d4)-b5 and everything unlocks.

In order for the cage to open, a black Queen has to screen on b1. Attempting to unpromote bSe4 and wSc6 on h1 and g8 right away and then uncapture the necessary Queen by means of h6xQg7 is one move too slow and white ends up retro-stalemated. (A)

Cooked by Henrik Juel: -1...Bd8xQc7+ (also -1…Bd8xRc7+) -2.a2-a3 Sf6-e4 -3.e4-e5 Se8-f6 -4.Se5-c6 Sf6-e8 -5.Sd7-e5 Se8-f6 -6.Qc4-c7 Sc7-e8+ -7.Sc5-d7 Sd4-b3 -8.Sb3xPc5+ Sf5-d4 -9.Qg8-c4 Sg3-f5 -10.Qh8-g8 Sh1-g3 -11.Qg8-h8 h2-h1S -12.Qh8-g8 h3-h2 -13.Qg8-h8 h4-h3 -14.Qh8-g8 h5-h4 -15.Qg8-h8 h6-h5 -16.g7-g8Q h7-h6 -17.h6xQg7 Qd4-g7 -18.h5-h6 Qb4-d4 -19.h4-h5 Qa3-b4 -20.h3-h4 Qb2-a3 -21.h2-h3 Qb1-b2 -22.e3-e4 Kc1-c2 -23.Sd4-b3+

The following correction is possible:

R0183 (v) Nikolai Beluhov, Correction by Andrey Frolkin

SRR5/Bpb1p3/pKSp4/rS2P1p1/B3s3/PsP2P2/2kPPp2/Q2b4]

Check? (15+12)

R0184 -

StrateGems, No. 55, Jul-Sep 2012

14+16. s#1 before 75 moves (Help-retractor, Circe)

[8/8/p7/1PpP4/1PkP1PPP/1RppbpPR/1bpBrrp1/n1KnqbNB]

Solution

Retract: -1.…Ba3xSb2+!! (To demonstrate the change of roles, the moves of this S will be underlined, and the moves of the other S will be written regularly) -2.Sa4-b2+ Sb2xQd1+ -3.Rh2-h3 d6xSc5(+Sg1) -4.Se4-c5 a7-a6 (To open the cage, two bPs are needed on the East side of the board. The a-pawn supports the transportation of the d-Pawn to the e-file; then the pawns change roles in order to shift the a-pawn to the h-file) -5.Sc5xPa4(+Pa7) a5-a4 -6.Sg5-e4 a6-a5 -7.Sa4-c5 a7-a6 -8.Sc5xPa4(+Pa7) a5-a4 -9.Sh3-g5 a6-a5 -10.Sg1-h3 e7xSd6(+Sg1) -11.Se4-d6+ a7-a6 -12.Sg5xPe4(+Pe7) e5-e4 -13.Sa4-c5 e6-e5 -14.Sc5xPa4(+Pa7) a5-a4 -15.Se4-c5 e7-e6 -16.Sf6xPe4(+Pe7) e5-e4 -17.Sh3-g5 e6-e5 -18.Se4-f6 e7-e6 -19.Sg5xPe4(+Pe7) e5-e4 -20.Sg1-h3 b6xSa5(+Sg1) -21.Sb7-a5+ e6-e5 -22.Sc5-b7 b7-b6 -23.a4xb5(+Pb7)! b6-b5 -24.Se4-c5 e7-e6 -25.Sc5xPe4(+Pe7) e5-e4 -26.Sh3-g5 e6-e5 -27.Sg1-h3 c7xSb6(+Sg1) (The wSs change roles) -28.Sd7-b6+ e7-e6 -29.Se4xPc5(+Pc7) c6-c5 -30.Sg5xPe4(+Pe7) e5-e4 -31.Sc5-d7 c7-c6 -32.Se4xPc5(+Pc7) e6-e5 -33.Sh3-g5 e7-e6 -34.Sg1-h3 d6xSc5(+Sg1) (2nd change) -35.Sg5xPe4(+Pe7) e5-e4 -36.Sh3-g5 e6-e5 -37.Se4-c5 e7-e6 -38.Sg5xPe4(+Pe7) e5-e4 -39.Sg1-h3 e7xSd6(+Sg1) (3rd change) -40.Se4-d6+ e6-e5 -41.Sc5xPe4(+Pe7) e5-e4 -42.Sh3-g5 e7-e6 -43.Sg1-h3 f6xSe5(+Sg1) (4th change) -44.Sf7xPe5(+Pe7)+ e6-e5 -45.Sg5-f7 f7-f6 -46.Se4-c5 e7-e6 -47.Sf6xPe4(+Pe7) e5-e4 -48.Sh3-g5 e6-e5 -49.Sg1-h3 e7-e6 -50.Se4xPf6(+Pf7) g7xSf6(+Sg1) -51.Sg5xPe4(+Pe7) e5-e4 -52.Sh3xPg5(+Pg7) e6-e5 -53.Sg1-h3 h6xSg5(+Sg1) (5th change) -54.Se4-f6 e7-e6 -55.Sf6xPe4(+Pe7) e5-e4 -56.Sh3-g5 e6-e5 -57.Se4-f6 e7-e6 -58.Sg5xPe4(+Pe7) e5-e4 -59.Sg1-h3 f6xSe5(+Sg1) -60.Sf7-e5+ h7-h6 -61.Sh6-f7 f7-f6 -62.Sf5xPh6(+Ph7) h7-h6 -63.Sh6xPf5(+Pf7) f6-f5 -64.Sh3-g5 f7-f6 -65.Sf5xPh6(+Ph7) h7-h6 -66.Sh6xPf5(+Pf7) f6-f5 -67.Sg1-h3 f7-f6 -68.Sf5xPh6(+Ph7) h7-h6 -69.Sh6xPf5(+Pf7) f6-f5 -70.Rh3-h2 f7-f6 -71.Sf5xPh6(+Ph7) h7-h6 -72.Sh6xPf5(+Pf7) f6-f5 -73.Sf5xPh6(+Ph7) g7xSf6(+Sg1) (6th change) -74.h2xPg3(+Pg7) g7xPh6(+Ph2) -75.Rh2-h3 Sd1xQb2(+Qd1)!! (Circe miracle! The pieces switch places. This hidden tempo was prepared from the very beginning) -76.h3xPg4(+Pg7) and s#1 by 1.Rxc3(+Pc7)+ Sxc3#

Try 1: Retract: -1…Ba3xQb2+ -2.Rh2-h3 d6xSc5 -3.Sa4-c5 e7xSd6(+Sg1) -4.Sf5-d6+ a7-a6 -5.Sc5xPa4(+Pa7) a5-a4 -6.Se4-c5 a6-a5 -7.Sc5xPe4(+Pe7) a7-a6 -8.Sa6-c5 e5-e4 -9.Sc7xPa6(+Pa7) and s#1 by 1.Rxc3+ Sxc3#, but there is no tempo at the very end (see the solution), which means that this position is illegal.

Try 2: Retract: -1…Ba3xSb2(+Sg1)+ -2.Sa4-b2+ Sb2xQd1+ -3.Rh2-h3 c7-c5 -4.Sc5-a4 a7-a6 -5.Sa4xPc5(+Pc7) c6-c5 -6.Sc5xPa4(+Pa7) c7-c6 -7.Se4xPc5(+Pc7) a5-a4 -8.Sg5-e4 a6-a5 -9.Sh3-g5 a7-a6 -10.Sg1-h3 d6xSc5 -11.Sa4-c5 d7-d6 and there is no way to uncapture this pawn at d6. If -11... Sd1xQb2(+Qd1), or -11…e7xSd6(+Sg1) -12.Se4-d6+ Sd1xQb2(+Qd1) there is no tempo at the very end; a fact that renders the position illegal.

The only way to release the position is to save the hidden tempo Sd1xQb2(+Qd1) for the very end of the retro-play. The Knights change roles 6 times. The Pawns change roles. (A)

P0281v -

StrateGems, No. 55, Jul-Sep 2012

[rnbBkbnN/pppppppp/7R/8/8/2N5/PPPPPPPP/RqrQKB2]

Solution

1.c4 d5 2.cxd5(+bPc4) c3 3.Sxc3(+bPb1=R) Rxc1(+wBb1) 4.Bxh7(+bPb1=Q) Qxd5(+wPd8=B) 5.Bc2(=wP) Rxh2(+wPh8=S) 6.Sf3 Rh7(=bP) 7.Rh6 Qd7(=bP) 8. Sh2(=wP)

P0297v -

StrateGems, No. 55, Jul-Sep 2012

13+13. PG 30

[3q2rr/1p1bn2k/2B1pn2/b2pp1B1/3pP3/3K1P1N/2PNPP2/3QR2R]

Solution

1.h4 e5 2.h5 Qg5 3.h6 Qe3 4.dxe3 a5 5.Qd4 a4 6.Kd2 a3 7.Kd3 axb2 8.a4 Bb4 9.a5 Se7 10.a6 0-0 11.hxg7 c5 12.Rh6 cxd4 13.Re6 fxe6 14.a7 Rf3 15.gxf3 h5 16.Bh3 h4 17.Bf5 h3 18.Be4 h2 19.Bc6 h1R 20.e4 Rh8 21.Sh3 Kh7 22.g8R d5 23.Rg1 Sd7 24.Bg5 Sf6 25.Sd2 Bd7 26.Rae1 Rag8 27.a8Q b1Q 28.Qa1 Ba5 29.Rh1 Qb6 30.Qd1 Qd8.

P0307 -

StrateGems, No. 55, Jul-Sep 2012

14+14. PG 5½ 2 solutions

[rnb1kbnr/pppp1ppp/8/8/3P4/1P6/P1P1PPPP/RN2KBNR]

Solution

1.b3 e5 2.Bb2 e4 3.Bf6 e3 4.dxe3 Qxf6 5.Qd4 Qxd4 6.exd4 ii) 1.b3 e6 2.Bb2 Qf6 3.Bc3 Qxc3 4.dxc3 e5 5.Qd4 exd4 6.cxd4.

P0308 -

StrateGems, No. 55, Jul-Sep 2012

14+15. PG 11½

[r1b1kbnB/pp1ppp2/2pr2p1/4n2p/1P6/5P2/P1PPP1PP/RN1K2NR]

Solution

1.b4 h5 2.Bb2 Rh6 3.Qc1 Rd6 4.Kd1 g6 5.Bh8 Sc6 6.Qa3 Se5 7.Qg3 c6 8.f3 Qb6 9.Qe1 Qf2 10.Kc1 Qxf1 11.Qd1 Qxd1+ 12.Kxd1.

P0309 -

StrateGems, No. 55, Jul-Sep 2012

12+13. PG 15½

[bnBqkb1r/r1ppppBp/2p5/8/2N5/P2P4/3P2PP/K2Q2NR]

Solution

1.e4 a5 2.Ba6 a4 3.Ke2 a3 4.Kd3 axb2 5.Sa3 b1Q (tempo!, if 5...b1R? 6.Bb2 Rc1 7.Bxg7 Sf6 8.Kc3 ~ 9.Kb2 Sxe4 10.Rxc1, but 8...??) 6.Bb2 Qc1 (tempo!) 7.Bxg7 Sf6 8.Kc3 Qb2+ (tempo!, if 8…~ 9.Rxc1 Sxe4+ 10.Kb2, but 8…??) 9.Kxb2 Sxe4 10.Rc1 Sxf2 11.Ka1 Sd3 12.cxd3 Ra7 13.Rc6 bxc6 14.Sc4 Bb7 15.a3 Ba8 16.Bc8.

A 3-move tempo maneuver (bQ promotion, bQ waiting move on c1 and Rundlauf on b2). (A)

P0310 -

StrateGems, No. 55, Jul-Sep 2012

15+14. PG 15½

[q4bnr/r1pppppp/b4Q2/n5B1/8/1P6/2PPPPPP/Rk1NKBNR]

Solution

1.a4 b5 2.axb5 Sc6 3.Rxa7 Sa5 4.Ra6 Ra7 5.Rh6! Ba6 6.b3 Qa8 7.Bb2 Kd8 8.Bf6 Kc8 9.Sc3 Kb7 10.Qa1 Kb6 11.Sd1 Kxb5 12.Bg5 Kb4 13.Qf6 Ka3 14.Rh4 Ka2 15.Ra4+ Kb1 16.Ra1+.

P0311 -

StrateGems, No. 55, Jul-Sep 2012

Dedicated to Nicolas Dupont

14+13. PG 16

[2k2bn1/p3ppp1/2p4r/6R1/3p4/1b4Pr/1PPPPPP1/RNBQKBn1]

Solution

1.Sf3 d5 2.Se5 Be6 3.Sd7 c6 4.Sxb8 Qxb8 5.a4 Qg3 6.hxg3 d4 7.Rh5 Bb3 8.Rg5 h5 9.a5 h4 10.a6 h3 11.axb7 h2 12.b8S Rh3 13.Sd7 0-0-0 14.Se5 Rd6 15.Sf3 Rdh6 16.Sg1 hxg1S.

This PG shows what Nicolas Dupont calls "symmetric” (or "quantic”) Pronkin: anti-Pronkin is captured on the promotion square and Pronkin is captured on the original square. (A)

P0312 -

StrateGems, No. 55, Jul-Sep 2012

12+13. PG 19½

[rnb5/q1b1k3/pppp4/5p2/3P2n1/P3P3/P1P2r1P/RN1QK1NR]

Solution

1.f4 a5 2.f5 a4 3.f6 a3 4.fxg7 f5 5.g4 Sf6 6.g8B Bh6 7.Bd5 Rg8 8.Bc6 dxc6 9.g5 Qd4 10.g6 Qa7 11.gxh7 Rg2 12.h8B Sg4 13.Bd4 Bf4 14.Bb6 cxb6 15.d4 Bc7 16.Bf4 Rf2 17.Bd6 exd6 18.e3 Ke7 19.Ba6 bxa6 20.bxa3.

Four bPs are displaced one line to the left, capturing the two original and two promoted Bishops. The content can be described as quadruple Massive Displacement by (IP & CF)(bb) & IP(bb), where CF is Ceriani-Frolkin and IP is Impostor Pawn (a pawn not originally from the line where it stands). See also P0304 from SG54. (A)

P0313 -

StrateGems, No. 55, Jul-Sep 2012

13+13. PG 24

[1n1q2nr/2p3p1/pp2b1k1/1K1p4/2Br4/bP4PN/1PPP2P1/RN1Q2R1]

Solution

1.f4 h5 2.f5 h4 3.f6 h3 4.fxe7 f5 5.e4 Kf7 6.e8R f4 7.Re6 f3 8.Rb6 f2+ 9.Ke2 axb6 10.Kd3 Kg6 11.Kc4 Ra4+ 12.Kb5 Rd4 13.Bc4 f1S 14.e5 Sg3 15.hxg3 h2 16.Sh3 d5 17.Rg1 h1S 18.e6 Sf2 19.e7 Sd3 20.e8R Sxc1 21.Re3 Be6 22.Ra3 Sb3 23.Ra6 Ba3 24.axb3 bxa6+. This PG shows (CC&CF)(RR) & CF(ss); probably the first bi-colored Ceriani/Frolkin, including cross-capture of one pair. (A)

The author offers a more economical version that replaces the original P0313:

P0313v Silvio Baier

14+13. PG 21½

[1nbq2nr/2pp2p1/pp6/7k/1b6/r1P2KPN/P1PPB1P1/RNBQ2R1]

1.f4 h5 2.f5 h4 3.f6 h3 4.fxe7 f5 5.e4 Kf7 6.e8R f4 7.Re6 f3 8.Rb6 f2+ 9.Ke2 axb6 10.Kf3 Kg6 11.Be2 f1S 12.e5 Sg3 13.hxg3 h2 14.Sh3 Kh5 15.Rg1 h1S 16.e6 Sf2 17.e7 Se4 18.e8R Sc3 19.Re4 Ra3 20.Ra4 Bb4 21.Ra6 bxa6 22.bxc3.

P0314 -

StrateGems, No. 55, Jul-Sep 2012

This problem was later found to be cooked

15+11. PG 28½

[rnbqkbnr/3p2p1/1R4P1/BBpP2B1/P5P1/N1R5/2QP1N2/2BK4]

Solution

1.f4 a5 2.f5 a4 3.f6 a3 4.fxe7 axb2 5.a4 c5 6.Sa3 b1Q 7.exd8B Qb6 8.Bg5 Qd8 9.e4 b5 10.e5 b4 11.e6 b3 12.e7 b2 13.exd8B b1Q 14.Ba5 Qb6 15.Rb1 Qd8 16.Rb6 f5 17.Bb5 f4 18.c4 f3 19.Qc2 f2+ 20.Kd1 f1B 21.h4 Bd3 22.h5 Bg6 23.hxg6 h5 24.Rh3 h4 25.Rc3 h3 26.g4 h2 27.Sh3 h1B 28.Sf2 Bd5 29.cxd5.

This is closely related to my P0279 (See SG51), but the combination of Ceriani/Frolkin (bb) & Pronkin (qq) is shown this time (A)

Hans Nieuwhart sent in a cook for R0179: Retract: 1…Sf4 2.Rc8 a6xRb5! 3.Rb8 Sg2 4.Rc8 Sh4 5.Rb8 Sf5 6.Rc8 Sd6 7.Rb8 Sc8 8.Se6 Qe7 9.Sf8+ Qe1 10.Rb6 Sf5 11.Kc4 d6+ etc. (captures Black: axb6 (promoted cPawn), fxg6 (promoted ePawn), gxBf6, exd - White: bxc).

The composers propose the following correction:

R0179v Nikolai Beluhov & Andrey Frolkin

12+15. Release the position

[bR1NkqQB/1NPrnRPr/2B1nppp/bpKp4/1p1p4/8/5P1P/8]