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In standard chess rules, a pawn is promoted if it reaches the far side of the board. Usually, the pawn's owner chooses to promote it to a queen.

Is it possible for one player to eventually promote all their pawns to queens, in a legal game of chess? Assume the opposing player plays "perfectly badly" to allow this. However, if the game reaches checkmate, it must stop.

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    $\begingroup$ Bonus: is it possible if both players have 9 Queens? $\endgroup$ – William Nathanael Dec 4 '17 at 14:00
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    $\begingroup$ That seems like it's worth a question in its own right - I'll pose it later unless you want to, William. $\endgroup$ – TenMinJoe Dec 4 '17 at 15:33
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    $\begingroup$ Related: Find the shortest chess game with 18 queens? $\endgroup$ – Stevoisiak Dec 4 '17 at 21:49
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    $\begingroup$ @Lolgast It actually seems like white's play is pretty good, in the sense that if you opponent is going to allow you to queen 8 pawns you should take the opportunity to do so, and then checkmate easily once you have them. $\endgroup$ – jwg Dec 5 '17 at 9:02
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    $\begingroup$ @jwg Well, by chess standards, missing 26 mate-in-ones, 4 mate-in-twos and one each of a mate-in-three, -seven, -eight and -nine would be considered pretty bad. In fact, there are only 6 positions in which the lichess analyzer (stockfish, depth 25) doesn't have a mate ready, including the starting position. Additionally, two of those 6 have a plus score of about 25. $\endgroup$ – Lolgast Dec 5 '17 at 10:50
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This 40 move solution on lichess works, and while it may not be the most orderly solution, it is impossible to create a solution in fewer moves since I'm using optimal pawn movement at every step and no other pieces (6 fields to move, 2 in the initial move, so 5 moves for each pawn to promote).

PGN of the game:

1. e4 f5 2. exf5 Kf7 3. f6 Nh6 4. fxe7 Kg8 5. e8=Q Ng4 6. f4 h6 7. f5 Kh7
8. f6 Qe7+ 9. fxe7 Nc6 10. exf8=Q Nge5 11. g4 Nf7 12. g5 Kg6 13. gxh6 Kf5
14. hxg7 Nb4 15. g8=Q Rh5 16. h4 Rg5 17. h5 Nc6 18. h6 Nb4 19. h7 Nc6
20. h8=Q Nb4 21. d4 Nc6 22. d5 b5 23. dxc6 Bb7 24. cxd7 Bd5 25. d8=Q Be6
26. c4 Rh5 27. cxb5 Rg5 28. b6 Rh5 29. bxc7 Rb8 30. c8=Q Rb5 31. a4 Rg5
32. axb5 Rh5 33. b6 Rg5 34. bxa7 Rh5 35. a8=Q Rg5 36. b4 Rh5 37. b5 Rg5
38. b6 Rh5 39. b7 Rg5 40. b8=Q

GIF:

40 move solution

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    $\begingroup$ I think the chess animations might only be on the Chess Stack Exchange itself $\endgroup$ – phflack Dec 4 '17 at 16:37
  • $\begingroup$ @phflack chess.se has a replayer, but I wouldn't call it an animation. $\endgroup$ – Herb Wolfe Dec 4 '17 at 16:59
  • $\begingroup$ Perhaps chess.se has a separate replayer, but I've seen other posts on puzzling with just a gif, so that should work $\endgroup$ – Lolgast Dec 4 '17 at 17:21
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    $\begingroup$ @HerbWolfe I wouldn't, either. But it's much better than an animation, since it allows the reader to move backwards and forwards through the game at their own pace. $\endgroup$ – David Richerby Dec 4 '17 at 19:38
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    $\begingroup$ @DavidRicherby Absolutely it's better than the animated .gifs. I personally find them to be annoying. $\endgroup$ – Herb Wolfe Dec 4 '17 at 21:34

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