3

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.

6
  • 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, 2015 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, 2015 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. 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, 2015 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, 2015 at 23:19
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    presumably there are also kings on the board.
    – hkBst
    Feb 12, 2016 at 9:20

2 Answers 2

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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#
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  • Very nice position ! (+1)
    – Peter
    Aug 12, 2018 at 11:03
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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! =)

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  • This is 7 moves? It looks like three: Kc2+ Ka2 Qb1+ Ka3 Qb3#.
    – D M
    Jul 22, 2018 at 22:05
  • @DM do you have any chess engine? load this up, ask to analyze...
    – lenik
    Jul 22, 2018 at 23:08
  • @DM ok, from another posts, I can see the concept of sacrificing the queen to postpone the mate is somehow unfamiliar to you. so here it is: Kc2+ Qg2 -- start from here and go up to 7 moves =)
    – lenik
    Jul 22, 2018 at 23:57
  • OK, I'm wrong, you're right.
    – D M
    Jul 23, 2018 at 1:28
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    @DM no worries, everyone is wrong sometimes =)
    – lenik
    Jul 23, 2018 at 7:04

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