# PG in 18.0 moves [2/22]

SwissGambit
Posers and Puzzles 23 Feb '08 01:02
1. SwissGambit
Caninus Interruptus
23 Feb '08 01:02

Proof game in 18.0 moves

[Find a legal game that reaches this position after Black's 18th move]

This ought to keep you guys busy for a little while...
2. 25 Feb '08 09:31
1. c4 e5 2. c5 Qh4 3. c6 Ne7 4. cxb7 c5 5. d4 Nc6 6. b8=Q exd4 7. Qg3 Ba6 8. f4 O-O-O 9. f5 Re8 10. f6 Nd8 11. fxg7 f5 12. g8=Q Bh6 13. Q8b3 Bxc1 14. e3 f4 15. Qb8 Kxb8 16. Be2 Nc8 17. Kf1 Rxe3 18. Qg8 Rxg8

Each promoted queen is captured on the other one's promotion square.
3. 25 Feb '08 13:362 edits
I always wondered about these proof games..is there always only one answer or can there be multiple answers?

EDIT: In other words, there are mate in x problems where you can mate in x moves in y different ways...are there some proof games like this? Or does that defeat the purpose?
4. 25 Feb '08 16:443 edits
Originally posted by tomtom232
I always wondered about these proof games..is there always only one answer or can there be multiple answers?

EDIT: In other words, there are mate in x problems where you can mate in x moves in y different ways...are there some proof games like this? Or does that defeat the purpose?
There are proof games with more than one solution, but that should be part of the stipulation. If the stipulation does not mention multiple solutions then there must be only one solution.
This is true not only for proof games but for all types of chess problems.

Example of a multiple-solution PG:

Peter Wong
Problem Observer, 1995
First prize

Proof game in 6.5 moves (3 solutions)

Which means: find 3 ways to reach this position after White's seventh move.