- Joined
- 20 Sep 01
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@BigDogg
I had to Google this
A proof game is a type of retrograde analysis chess problem. The solver must construct a game starting from the initial chess position, which ends with a given position (thus proving that that position is reachable) after a specified number of moves.
How can that situation be attained?
Had a look last night.
Working on a theory the b-pawn takes on a2, b1 Knight off taking things, the
h8 Rook, the e7 pawn and c8 Bishop. a1 rook moves to b1, black pawn on a2
promotes to Rook, that Rook goes to b5 or c6, white b1 Rook goes back to a1
to vacate b1 for Knight to return home. (or something like that.)
@greenpawn34 saidA good way to begin is to list each piece and count the minimum number of moves it needs to reach its destination.
Had a look last night.
[fen]3n4/p2p1ppp/1qr1k3/1rp5/4n3/b7/1PPPPPPP/RNBQKBNR w[/fen]
Working on a theory the b-pawn takes on a2, b1 Knight off taking things, the
h8 Rook, the e7 pawn and c8 Bishop. a1 rook moves to b1, black pawn on a2
promotes to Rook, that Rook goes to b5 or c6, white b1 Rook goes back to a1
to vacate b1 for Knight to return home. (or something like that.)
For black:
K takes 2 moves
Q takes 1
Rs take 2 each
Bf8 takes 1
Nf6-e4 is 2
Nc6-d8 is 2
c7-c5 is 1
----
13 moves total
Given that the stipulation is 13 moves, black has no spare time.
This means he can't move the b7 pawn. White has to clear that out for him, along with the other missing pawn and B.
@greenpawn34 saidThat's a good start.
This is the best I can do so far.
[pgn]
1.Nf3 e5 2.Nxe5 Nf6 3.a3 Bxa3 4.Ng6 c5 5.Ne7 Nc6 6.Nxc8 Rb8 7.Nd6+ Ke7 8.Nxb7 Ke6 9.Nd6 Rb5 10.Nf5 Qb6 11.Nh4 Rc8 12.Nf3 Nd8 13.Ng1 Rc6 {That is 13 moves, I am a move short. It is the e7-e5 move.} [/pgn]
From the opening, Black has two moves he can play without any help from white: Ng8-f6, and Nf6-e4.
So the new goal is to find some white moves that help black make a move that is on the 'permitted moves' list. White has 3 moves to do something that gives black a move. What can he do?
@greenpawn34 said3...Kxe7!
This is best I can do, I am probably being stupid missing something obvious.
I've given up.
[pgn]
1. Nc3 Nf6 2. Nd5 Ne4 3. Nxe7 Na6 4. a3 Rb8 5. Nxc8 Bxa3 6. Nd6+ Ke7 7.
Nxb7 c5 8. Nd6 Rb5 9. Nc4 Qb6 10. Ne3 Rc8 11. Nd5+ Ke6 12. Nc3 Rc6 13. Nb1
Nb8[/pgn]
Edit: thanks for being a good sport and giving this a try even though I know these aren't your favorite type of problem.
@greenpawn34 saidSOLV'D
At last!
[pgn]
1. Nc3 Nf6 2. Nd5 Ne4 3. Nxe7 Kxe7 4. a3 Ke6 5. a4 Ba3 6. a5 c5 7. a6 Nc6
8. axb7 Rb8 9. bxc8=N Rb5 10. Ne7 Qb6 11. Nd5 Rc8 12. Nc3 Nd8 13. Nb1 Rc6
[/pgn]
This was composed by a person on another site.
I thought it was a good intro problem. The theme is sacrificing an N, promoting a replacement, and bring it home (Pronkin theme). The tempo move a3! is a nice touch.