- 25 Aug '06 18:03

Retract:*Originally posted by David113***A nice retro problem I saw recently:**

a) Compose a proof game for this position

[fen]2B5/pr1pPpp1/k5p1/P3Qp2/Kp6/1rP4P/PPp1P2P/R3N2R[/fen]

Give all the moves.

b) Did you notice something special in the proof game?

-1.Rd1-a1 f6-f5 -2.Rd5-d1 h7xNg6 -3.Rb5-d5 Rc7-b7 -4.Rb7-b5 Rc6-c7 -5.Qe4-e5 Rd6-c6 -6.e6-e7 Rc6-d6 -7.e5-e6 Re6-c6 -8.f4xBe5 Re8-e6 -9.f2-f4 Rh8-e8 -10.Nf3-e1 Bd6-e5 -11.Ra1-h1 Bf8-d6 -12.Nh4-g6 e7xBf6 -13.Bg5-f6 Rg8-h8 -14.Bc1-g5 Rh8-g8 -15.d2xQc3 Qc5-c3 -16.Qf5-e4 Rd3-b3 -17.Kb3-a4 Rd6-d3 -18.a4-a5 Kb6-a6 -19.Rc7-b7 etc.

(No need to continue retracting to the start position, because this is obviously legal.)

The white Rooks swapped places (a1/h1) during the game. - 25 Aug '06 22:40 / 1 edit

I'm sure I've posted this before, but this will save the trouble of a forum search.*Originally posted by David113***Excellent!**

I wonder if the same can be done with knights.

Satoshi Hashimoto*StrateGems*1999

Proof Game in 15.5 moves

(White has just made his 16th move. Find the gamescore.) - 28 Aug '06 06:23

Solution:*Originally posted by BigDoggProblem***I'm sure I've posted this before, but this will save the trouble of a forum search.**

Satoshi Hashimoto*StrateGems*1999

[fen]qk3b1r/2p2ppp/1pn3n1/2pppb2/8/5P2/P1PP1PPP/RNBQK1NR b KQ - 0 16[/fen]

Proof Game in 15.5 moves

(White has just made his 16th move. Find the gamescore.)

1. b4 d5 2. b5 Bf5 3. b6 axb6 4. Nf3 Ra3 5. Ne5 Rf3 6. Nd7 e5 7. exf3 Ne7

8. Bb5 Ng6 9. Bc6 bxc6 10. Nc3 c5 11. Ne2 Nc6 12. Ng1 Qa8 13. Nf6+ Kd8 14. Ne4 Kc8 15. Nc3 Kb8 16. Nb1 - 28 Aug '06 09:54

Keys to the solution: rook goes up from c1 (not d1), and the black nights swap position.*Originally posted by David113***More of the same...**

[fen]rnbqkbnr/pppppppp/2Q2R1B/8/2P1PP2/5N2/PP1N2PP/4KB1R[/fen]

SPG in 12.0 moves

1.c4 Nf6 2.Qa4 Ne4 3.Qc6 Nxd2 4.e4 Nb3 5.Bh6 Na6 6.Nd2 Nb4 7.Rc1 Nd5 8.Rc3 Nf6 9.Rf3 Ng8 10.Rf6 Nc5 11.f4 Na6 12.Ngf3 Nb8. - 28 Aug '06 17:13 / 1 edit

1.b4 c5 2.b5 Qc7 3.b6 Qg3 4.hxg3 h6 5.Rxh6 axb6 6.Rc6 Rxa2 7.Na3 Rxc2 8.Bb2 Rc4 9.Nc2 Rch4 10.e4 g6 11.Bc4 Bh6 12.Ne2 Be3 13.dxe3 e6 14.Qd3 Ne7 15.O-O-O O-O 16.Rxc8 Nbc6 17.Ra8 Rh8 18.Ra1 Ra8 19.Rh1 Nb8*Originally posted by David113***And another ...**

[fen]rn4kr/1p1pnp2/1p2p1p1/2p5/2B1P3/3QP1P1/1BN1NPP1/R1K4R w - - 0 1[/fen]

SPG in 19.0 moves

(Is it possible to insert more than one diagram in a post? when I tried it didn't work, that's why I you see 3 posts for 3 problems.)

Both Ra1/Rh1 and Ra8/Rh8 swap places.