# Proof Game in 26.5 moves

BigDoggProblem
Posers and Puzzles 17 Sep '06 06:50
1. BigDoggProblem
Just...the Dogg
17 Sep '06 06:50

PG in 26.5 moves
(position after White's 27th move; find the gamescore)
2. 17 Sep '06 16:45
Why does black have 3 knights?
3. Dragon Fire
Lord of all beasts
17 Sep '06 17:39
Originally posted by laedawg
Why does black have 3 knights?
Obviously he has "queened" a pawn.
4. 17 Sep '06 17:49
Why on Earth would you choose a Knight over a Queen?
5. 17 Sep '06 19:334 edits
Did you notice White has three rooks? ðŸ˜€
In a proof game the moves need only be legal - they do not have to make any sense as moves in an actual game.
Anyway, what would you play in this position (you are white and it's your turn):

And a set of little challenges (but don't forget BDP's problem!)
Find positions with minimal number of chessmen where:
1. Knight promotion is the only winning move;
2. Rook promotion is the only winning move;
3. Bishop promotion is the only winning move;
4. Knight promotion is the only drawing move (solution above);
5. Rook promotion is the only drawing move;
6. Bishop promotion is the only drawing move.
The best solutions I know of are as follows:
Challenge no. 1 - 4 pieces;
Challenge no. 2 - 3 pieces;
Challenge no. 3 - 5 pieces;
Challenge no. 4 - 4 pieces;
Challenge no. 5 - 7 pieces;
Challenge no. 6 - 6 pieces.
Can you find the positions?
6. Dragon Fire
Lord of all beasts
17 Sep '06 20:38
Originally posted by David113
Did you notice White has three rooks? ðŸ˜€
In a proof game the moves need only be legal - they do not have to make any sense as moves in an actual game.
Anyway, what would you play in this position (you are white and it's your turn):
[fen]4K3/r4P2/4k3/8/8/8/8/8[/fen]
And a set of little challenges (but don't forget BDP's problem!)
Find positions with min ...[text shortened]... ieces;
Challenge no. 5 - 7 pieces;
Challenge no. 6 - 6 pieces.
Can you find the positions?
f8=N+
7. BigDoggProblem
Just...the Dogg
18 Sep '06 06:242 edits
Originally posted by David113

And a set of little challenges (but don't forget BDP's problem!)

Can you find the positions?[/b]
Here's the first three:

1. Knight promotion is the only winning move;
wKf5 Bg6 Pg7; bKh6. 1.g8N+!
2. Rook promotion is the only winning move;
wKa5 Pc7; bKa7. 1.c8R!
3. Bishop promotion is the only winning move;
wKb4 Nd5 Pb7; bKa6 Pa7. 1.b8B!

The queen was left off the list, because that task isn't possible with 3 units, and trivial with 4 units.
8. BigDoggProblem
Just...the Dogg
18 Sep '06 06:26
Originally posted by laedawg
Why does black have 3 knights?
Probably for the same reason White has three Rooks.
9. BigDoggProblem
Just...the Dogg
19 Sep '06 21:01
Originally posted by David113

And a set of little challenges (but don't forget BDP's problem!)
Find positions with minimal number of chessmen where:

4. Knight promotion is the only drawing move (solution above);

Can you find the positions?
Seems there are multiple solutions for this one.

wKh5 Pe7; bKf6 Qg7

Menaced with ...Qg5#, White's only escape is 1.e8N+, winning the Queen and drawing.
10. BigDoggProblem
Just...the Dogg
19 Sep '06 21:213 edits
Originally posted by David113

And a set of little challenges (but don't forget BDP's problem!)
Find positions with minimal number of chessmen where:

5. Rook promotion is the only drawing move;

The best solutions I know of are as follows:
Challenge no. 5 - 7 pieces;
I can beat this by 2 units.

wKc1 Ph7; bKa1 Pa2h2.

Of course, White can win (1.h8Q#, 1.h8B# ) or lose (1.h8N, 1.K~) but only 1.h8R h1Q+ etc. draws.
11. BigDoggProblem
Just...the Dogg
19 Sep '06 21:33
Originally posted by David113

And a set of little challenges (but don't forget BDP's problem!)
Find positions with minimal number of chessmen where:
6. Bishop promotion is the only drawing move.

The best solutions I know of are as follows:
Challenge no. 6 - 6 pieces.
Using my idea from challenge #5, I can do this one with a mere 4 units.

wKc2 Pa7; bKa1 Ph2.

1.a8B is the only drawing move.
12. 20 Sep '06 16:09
When I wrote "move X is the only drawing move" I meant that all other moves are losing.
13. BigDoggProblem
Just...the Dogg
20 Sep '06 18:20
Originally posted by David113
When I wrote "move X is the only drawing move" I meant that all other moves are losing.
As my examples show, the stip must explicitly state this (or my examples become cooks).
14. 21 Sep '06 20:231 edit
Originally posted by BigDoggProblem
3. Bishop promotion is the only winning move;
wKb4 Nd5 Pb7; bKa6 Pa7. 1.b8B!
Wrong.

White mates in 103 (!) by 1.b8N.
15. BigDoggProblem
Just...the Dogg
22 Sep '06 05:16
Originally posted by David113
Wrong.

White mates in 103 (!) by 1.b8N.
Prove it.