In this endgame study I'm showing a rare ending involving a queen and knight vs. a queen. This is usually a draw since a knight usually isn't a significant attacker on a wide open board with queens. If the attacker's pieces are placed sufficiently close to the enemy king, and the attacker has the tempo, then sometimes there is an in-depth tactic to mate or win the queen. This endgame study will demonstrate that, and it will also help you better in calculating attacks.  | 
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1. e4 f5 2. Ke2 fxe4 3. Ke3 e5 4. Kxe4 Qh4+ 5. Kxe5 Qxh2+ 6. Kd5 Qxh1 7. Qh5+ Qxh5+ 8. Kc4 Qd1 9. d4 Qxc1 10. d5 Qxf1+ 11. Kd4 Qxb1 12. d6 Qxa1 13. dxc7 Qxa2 14. cxb8=Q Bc5+ 15. Kxc5 Qxb2 16. Qxa8 d5 17. Kxd5 Qxc2 18. Qxb7 Qxf2 19. Qxc8+ Kf7 20. Qd7+ Kf8 21. Qxg7+ Ke8 22. Qxg8+ Kd7 23. Qxh7+ Ke8 24. Qxh8+ Ke7 25. Qh7+ Kf8 26. Qxa7 Qxg2+ 27. Ke5 Qg6 28. Nf3 Qh6 29. Nh4 Qg6 30. Nf5 Qh7 31. Qb7 Qg6 32. Ke4 Qf6 33. Qd7 Qg6 
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Now, it would be very rare for this endgame to occur in a real game, but it's possible that this position and similar ones could pop up in some games, maybe after a series of mass exchanges. It's White's move here and there is one move that obtains the win. Seeing how White wins this ending should open your mind to deep attacking ideas because of the complexity of this study. | 
   
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34. Qe7+ 
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White has to keep the pressure on the king. Tempo and activity are the most important thing in endings regarding major pieces. If White doesn't check Black, then Black has the tempo and can draw with perpetual check. The only other checks allow Black to trade queens, which is a dead draw.  | 
   
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34... Kg8 
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White's illusory threat of Qg7# isn't much, but White's next zugswang tactic exploits that idea, forcing the queen to stay on the g-file to defend that threat. | 
   
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35. Ke5 
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White has hidden his king from queen checks, and Black is in zugswang. Black must move his queen to a safe square on the g-file to maintain the defense of the mate threat. If Black tries 35...Kh8, then 36.Qh4  Qh7 (Kg8 Ne7 ) 37.Qd8  Qg8 38.Qf6  Kh7 39.Qh6# | 
   
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35... Qg2 
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If Black plays Qg1, then White has an in-depth tactic to exploit the far placed queen 35...Qg1 36.Qe6  now if Black tries Kh7 or Kh8, then 37.Qh6  Kg8 38.Ne7  Kf7 39.Qe6  where Black gets his queen skewered after 39...Kg7 40.Qg8 , Black gets mated after 39...Ke8 40.Nd5  Kf8 (Kd8 Qd7 Kc8 Qc7#) 41.Qe7  Kg8 42.Nf6  Kh8 43.Qh7#, and Black also loses after 35...Qg1 36.Qe6  Kh 37.Qh6  Kg8 38.Ne7  Kf7 39.Qe6  39...Kf8 40.Ng6  Kg7 41.Qf6  and Black's queen will get skewered on the g-file since White can force Black to the h-file, after 41...Kh6 Nf8  Kh5 Qh8  Kg4 Qg8  (this won't work if Black's queen is on g2)
So Black is totally lost in all variations if he tries 36...Kh7 or 36...Kh8. 
Against 36...Kf8 in that variation, 37.Qh6  and if 37...Ke8, then 38.Nd6  and White has a mating attack with the queen and knight by checking every move. A sample mate is 37...Ke8 Nd6  Kd7 Qe6  Kc6 Qc8  Kb6 Qb7  Kc5 Qb5#
37...Kf7 also loses after Qh7  Kf8 Qh8  Qg8 (If Kf7 then Nd6  Ke7 Qe8#) Qf6  Qf7 Qd6  Ke8 Qb8  Kd7 Qb7  Ke8 Nd6 
37...Kg8 also loses since Ne7  Kf7 Qe6  reaches the position discussed at the top of this analysis, so after looking at all those variations, we can safely say that Qg1 loses in all variations, now let's look at Qg2. | 
   
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36. Qd8+ 
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Although Qg1 and Qg2 don't seem very different, they make White win in totally different ways. The queen skewering tactic doesn't work with the queen on g2 since it is close enough for the king to defend in that tactic. White needs to find a different way to win here, and the way will be getting the king to the 6th rank to overload Black with mate threats. The king cannot get to the 6th rank now because of perpetual check from Black, so White needs to maneuver the queen to a square that will block queen checks. The square White needs to go to is c7, to stop Qc6  after Kf6. White's queen can take away Black's queen's squares using checks to maneuver it to c7. This attacking idea wouldn't have worked with the black queen on g1, since the queen controls too many squares from there. White had two very different winning ideas, which were based on where Black chose to move his queen on move 35. | 
   
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36... Kh7 
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Kf7 loses to Nh6  where Black gets skewered next move | 
   
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37. Qc7+ 
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White's queen has gotten to the desired square using checking tempos. Black can play Kg8 or Kh8 here, but Black's king is still cornered and White uses tactics to exploit it in any case. | 
   
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37... Kg8 
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If Kh8, then 38.Kf6 and play is similar to the text. White intends to play Qe5, reaching a similar position to move 39. If 38...Kg8 then Nh6  initiates the threat White has next move. | 
   
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38. Kf6 
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The key squares controlled by the White queen are b6, c6, g3, and c2.
Control of c6 prevents Qc6 
Control of b6 prevents Qb2  Kg6 Qb6 
Control of g3 allows Qb2  Kg6 Qg2  Ng3 where all of Black's checks are blocked, and Black cannot stop both mate threats of Qg7# and Qd8# 
Since checking White gives White the unstoppable mating threats, Black's only move is 38...Kh8, since White is threatening Nh6  Kh8 Nf7  Kh7 (Kg8 Qd8  Kh7 Qh8#) Ng5  and Black loses with Kh6 Qh7# or Kg8 Qh7  Kf8 Qf7# | 
   
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38... Kh8 39. Qe5 
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This position is similar to one discussed a couple moves ago, but the placement of the Black queen doesn't matter since White's discovered check threat defends against possible queen checks from Black. | 
   
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39... Kh7 
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Black stops the discovered check threat. Kg8 does also, but Ne7  and Black is mated next move. Black's other defensive tries also lose.
If 39...Qg8 then 40.Qd4 and White threatens Qh4#, while also maintaining the discovered check possibility, which leads to mate since Black's queen is forced off g8, freeing f7 and g6 for the White king to assist in the mate.
If 39...Qg4, then Kf7  Kh7 Qh2 
If Black moves queen off g-file, then Kg6  Kg8 Qe8#
If 39...Qg1, then Ng3 blocks the g-file and Black's queen can no longer stop White from doing the discovered check mating sequence. King moves from Black just allow a mating attack from several queen checks | 
   
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40. Qe7+ 
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This checking process will reach a position similar to the position before Kh7, except that one difference will make it so that Black cannot play Kh7. | 
   
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40... Kh8 
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Kg8 would allow Nh6  Kh8 Nf7  where Black is mated after (Kh7 Ng5  Kg8 Qe8#) or (Kg8 Qe8  Kh7 Qh8#) | 
   
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41. Qe8+ 
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This forces Qg8, since Kh7 loses to Qh5  Kg8 Ne7  Kf8 Qh8# | 
   
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41... Qg8 42. Qe5 
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This position is almost the same as on move 39, except that Black's queen has been forced to g8. Since White has forced Black to block a square from his king, Kh7 (played on move 39) is now met by Qh2#
Now Black's queen must move, and depending on where Black moves the queen, White will transpose into one of the positions discussed on move 39 because of this tempo gain. | 
   
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42... Qg1 
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Qf8  allows Kg6  Kg8 Nh6  and Black's only legal move is giving up the queen.
Qg4 allows Kf7  Kh7 Qh2 
The text move reaches one of the winning variations I discussed on move 39 about how Black loses if he doesn't play Kh7.
Qg2 would reach the exact same position after White's 39th move, except that it is White's move because of White's tempo gain. Qg1 and Qg2 both lose to Ng3 | 
   
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43. Ng3 
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If you don't remember this position from my analysis on move 39, this move blocks the g-file and Black's queen can no longer stop White from doing the discovered check mating sequence. King moves from Black just allow a mating attack from several queen checks. No matter what Black does here, White will be able to mate in 3 moves or less.  | 
   
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43... Kg8 44. Qb8+ Kh7 45. Qb7+ Kh6 46. Qg7# 
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Even though the chances of this endgame occurring are very slim, hopefully studying the ideas and attacking sequences have helped you. | 
   
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