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Black and white both have one queen and the king. Is this game a draw?

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The side to move first in KQ vs KQ wins in 41.75% of the positions. That's because the side to move first gets the first check, which is often decisive in these major-piece endgames - compare how many KQQ vs KQQ positions, which ostensibly have equal material, are won by the side to move first (83%).

Caveat: "positions" here refers to all legal positions, some of which might not be realistic in practical play.

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    Correct answer to the wrong question – David Oct 11 '20 at 23:03
  • @David I don't understand your commend. – Allure Oct 12 '20 at 9:22
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    I agreed with David's comment until clicking the link and reading the article. The way this answer is worded it seemed like it was only talking about KQQ vs KQQ. Might be worth improving the answer to make that clearer by including the text from the article – Darren H Oct 12 '20 at 9:32
  • @Allure This question is about KQ vs KQ, not KQQ vs KQQ – David Oct 13 '20 at 7:36
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There are various positions that matter for pawn endgames. Often both sides promote to queen and then the side that moves first still wins.

This can happen right after promotion, when the king of the stronger side is close by.

Some examples:

[FEN "8/1KP1q3/8/8/3k4/8/8/8 w - - 0 1"]

1.Kb8?? {Ka8 is correct} Kc5! 2.c8=Q+ Kb6 {And white can't prevent checkmate}

and

[FEN "8/6p1/8/8/7k/5K2/2P5/8 w - - 0 1"]

1.Ke4! g5 2.c4 g4 3.c5 g3 4.Kf3 Kh3 5.c6 g2 6.c7 g1=Q 7.c8=Q+ {Check!} Kh4 {Otherwise Qh8#} 8.Qh8+ Kg5 9.Qg8+ {Wins the queen}

and

[FEN "8/8/8/p7/k7/3K4/3P4/8 w - - 0 1"]

1.Kc4! {Locking up the black king so it has to spend an extra tempo} Ka3 2.d4 Kb2 3.d5 a4 4.d6 a3 5.d7 a2 6.d8=Q a1=Q 7.Qd2+! Kb1 (7...Ka3 8.Qb4+ Ka2 Qb3#) 8.Kb3 {White wins. }

Source: 100 Endgames You Must Know, by Jesus de la Villa.

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  • Nice, helpful examples. – rolando2 Oct 12 '20 at 15:11
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Unless there is some forced sequence that leads to mate or either side losing the queen, King+Queen vs King+Queen will be an easy draw with correct play.

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    "Unless there is some forced sequence that leads to mate, it will be a draw with correct play" does this statement not apply to any position? – wimi Oct 12 '20 at 7:59
  • From a game theory perspective, yes. But those mating/ queen-losing sequences can be simply calculated by a human in a matter of seconds. – David Oct 12 '20 at 8:34

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