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What is the longest way to checkmate with 1 queen against 4 queens, with no other pieces on the board?

Since there are 13 moves long games with a queen vs two queens, I conjecture this should be possible also for this certain endgame, but I am not sure. The maximum position I know has the disadvantage that the first move is a capture. It would be nice if the first move is not a capture.

Rewan Demontay
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Peter
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  • I may have misread your question. I interpreted it as asking for the max DTM for the 4-queen side against the 1-queen side. Were you actually asking about the longest mate for the 1-queen side against the 4-queen side? Then your conjecture makes more sense to me. – ETD Mar 10 '15 at 22:52
  • Yes, I search the maximum DTM where ONE queen WINS against 4 queens and the first move is no capture. – Peter Mar 11 '15 at 17:08
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    Some info that doesn't speak directly to your conjecture, but is the most relevant I know: [Bourzutschky et al.](http://centaur.reading.ac.uk/4524/1/2005a_TCS_BTH_Chess_Endgames_6-man_Data_and_Strategy_-_preprint.pdf) indicate a max depth-to-*conversion* of 10 moves (see p.11) for a position where KQ-to-move wins against three queens. – ETD Mar 11 '15 at 21:50
  • Unfortunately, no example position is given. Otherwise, it might be possible to derivate an example with 4 queens as well. – Peter Mar 11 '15 at 23:19
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    presumably there are also kings on the board. – hkBst Feb 12 '16 at 09:20
  • @Peter can you post FEN for 13 moves for QvsQQ ? – lenik Jun 29 '18 at 13:15

2 Answers2

7

This max-DTZ position is mate in 8, but probably also a dead-end because it seems hard to improve starting here.

[FEN "7q/4q1q1/8/8/3q2Q1/1K6/8/1k6 w - - 0 1"]

1. Qf5+ Qde4 2. Qf1+ Qe1 3. Qd3+ Ka1 4. Qa6+ Qa5
5. Qxa5+ Qa3+ 6. Qxa3+ Kb1 7. Qa2+ Kc1 8. Qc2#
Niklas
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6

The best I could come up with is 7 moves, I don't believe it could take much longer, because with 4 queens there's not as much freedom as with 2, I cannot put black king in the middle of the board when capturing black queens while keeping king in check:

3q4/q7/q7/q7/8/8/8/k1K4Q w - - 0 1

And I made it nice as you asked -- the first move it not a capture! =)

lenik
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