Find the best move!
It’s White's turn to move. If both White and Black play optimally, what is the minimum number of moves for White to checkmate the Black king?
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5 solutions
I don't understand why it's not two moves. You can do a backup to the left with knight and go on top line with queen. Two moves checkmate.
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I thought similar, but with pawn promotion to queen; but Black can move pawn at h7 for an escape route.
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If Black moves pawn to H7, then you promote to Knight. But that is not checkmate, darn it.
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@Victor Shirosaki – Quite! So it's more than 2 moves for a checkmate. (Another one wrong for me :D)
1.Ng6+ hxg6 2.Qc8+ Kh7 ....... mate in four moves
That is wrong its possible in 2 move the queen then take the knight out checkmate
What if black's first step is g3 and second g4+
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I think in your question you are trying to say blacks first step is g3 and second g2+.
Answer for your question:
- Qf1, g3 2. Ng6+,hxg6 3. Qh3++
Thank you. I updated the solution.
Why not Qc8, then Kd7 or Ke6- two moves.
How do we log in? Use white knight to check king. Doesn't matter if it is taken. White pawn up, check mate.
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1.Ng6+, hxg6 2. g8(Q)+, Kh7 .. how it will end in check mate in three steps. It will take more than three steps. You forgot now King is able to move to h7.
Is there a way we can show that this is optimal without exhaustive search?
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First move is 1.Qf1 optimal. Based on the Black move we need to do further move.
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The question is how to prove that there is no 2-move solution without a far more exhaustive explanation.
This is wrong. The answer is two. Knight pits king in check. Pawn must kill knight. Pawn pushes and becomes rook. Checkmate!
- Qd3, Bb2 2. Qh7 <- Checkmate. There's only 2 moves needed if White is playing optimally and Black moves their Bishop first. Black's Bishop can't do anything to stop the queen from taking Black's Pawn at H7. But, Black would not be playing optimally that way. Black's 1st optimal move would be to move Pawn at G7 to G6. Then, White has no choice but to take Black's bishop to get a checkmate. But by then, G7 is open for the Bishop to move to. Black playing optimally would then choose not to attack White's Knight because their King would be left vulnerable to possible attack from White's Queen. From there, it would take many more moves for white to win. So 2 and 3 are both incorrect.
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1.Qd3 delays the mate in one move. The key move is Qf1!, then anything goes.
only two moves required
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It will take minimum three moves. Check your moves in the board. It will give better understanding.
The black can delay the check mate by moving the pawn on h4 forward and wasting a move by giving check.
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Be careful in analyzing. There is no black pawn in the h4 square.
pawn in not placed in h4 it is placed in g4 if it try to move g3 also we will mate by three moves
- Qf1, g3 2. Ng6+,hxg6 3. Qh3++
I don't understand, why not Queen to e4 then Queen to h7, therefore the mate is in two?
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white: queen to e4 then black: pawn to g6 ..... it is not mate in two..
Why isn't it one? Can't you move the white pawn to promote it to a queen, checkmating the king in one move? How can black get out of that?
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Unfortunately, the knight is blocking the pawn. There is no way the pawn can move in this move.
- Ng6+, hxg6, Qxg4, Bf6, Qh3+, Bh4, Qxh4#. 4 moves. Ne6 as the first move also mates in four. but there is no variant in which white mates in less moves assuming assuming black plays optimally. the answer they give, three, is just wrong. i even checked with a chess engine to make sure i wasn't crazy :))
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Ng6+ is a good move, but Qh1 is a better move. I don't know what your chess engine is, but the weakest chess engine will show that Qh1 is the best move for white. although white wins (Ng6+), but it is not the least number of moves as required in the problem.
knight to e6, pon to queen.... 2
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after knight to e6, black will move the h6 pawn to provide escape route for the black king. it becomes mate in four not three. although white wins, but it is not the least number of moves as required in the problem
I have an alternative solution . Please correct me if i am wrong. 1: knight to G6 check ! ,black has no option but to kill knight with pawn so black pawn to G6. 2 queen to G4 ,now black has many options like - A) king to G7 B) pawn to G5 C) bishop to anywhere possible . 3. In any case queen to h3 will be checkmate!!
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Check this comment by Horia Duţă . 2 ... Bf6 can help Black delay checkmate by one move.
I think it should be 1 move i.e move knight from f8 to g6 and then black king will be blocked and cannot move because if it moves it will be killed by bishop else by knight.
Knight G6 also works!
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If you do that, then pawn at h7 captures Ng6. What are your next moves?
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Queen capture G4, then checkmate king by moving to h column, no matter what black does. =)
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@Anonymous Zang – After Qxg4, black plays Bishop f6. The bishop can then go between white queen and the black king.
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@Pranshu Gaba – True! I was wrong, sorry. Thanks for the correction!
This is wrong because the black pawn on G7 could move up one causing this to not work.
It only take two moves right?
There 's a problem
How about: 1. knight to G6 (check) Black pawn must take knight 2. then White bishop takes pawn at G6. Black could do any move 3. then White queen to C8 (checkmate)
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h7 pawn already moved from its location. So, king can move to h7 for the check.
Queen to C8 then knight to E6. Mate in two moves. Even if black moves the pawn on G7 to G8 the king wouldn't be able to move to G7 because of the knight.
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After queen to c8, black will move the pawn at h7 to h6. Queen to c8 delays the mate. It becomes mate in four moves not three.
1.Qf1!!
Any bishop move leads to the queen forking the h7-square and the bishop. The only way black can stop mate then is g6, but then white can take the bishop with checkmate!
1...h6 or 1...h5 loses to 2.Qb1
1...g6 or 1...g5 loses to 2.Qxa1#
1...g3 2.Ng6+! hxg6 3.Qh3#
it can be done in 2 moves 1- move queen to right diagonal white box 2- then in right diagonal remove the black on left of king check and mate !
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Can you use proper chess notation please? I can't really understand!
In any interpretation of your vague description i can find, there's a way to stop any 2-move mate attempt. Sorry, but I can't agree with you without unambiguous chess notation.
Two moves: Qd3, then Qh7. would only require 3 moves if Black moves Pg7 to Pg6. Quenn would take pawn and then move to h7 next turn.
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What would the optimal move for black after Qxg6? Will it be possible for White Queen to take h7 in the next move?
Pg6 blocks Qh7 in that case
But first PxQ.
knight e6. pon f8. 2
this is the correct answer
This is hard one because it has many variations. Assuming that both White and Black play optimally, white will mate the Black king in three moves. So the hint is to look at the White King, it cannot move! The key move is Qf1! . After Qf1! , Black has many replies, then mate follows in a few moves.
I answered 2 but it was marked incorrect. You can mate in 2:
- Ng6+ hxg6 2. Qh4# hxg6 is forced as black has no other move out of check.
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how can Qh4 happen when there's a pawn blocking the way?
My bad. I missed the pawn on g4
Yes 2 you take the queen on the same line of the horse and you take the horse between the two soldiers and it's over for the blacks
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if you put the queen in line with the knight, black will play h6
I believe you could finish that in two steps .. if you push the king ahead to the edge (0,2) .. and shift the horse back to (1,3)
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Be careful in analyzing, the king cannot be the first move here. Remember that the queen is more powerful than the king and please use proper chess notation. No one knows where (0,2) is ..... or (1,3) ...
first move Qxg4
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Bf6 by black blocks any attempt to mate in 3 in this case
Why not 2 moves, Qd3 and Qh7?
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because Pg6 blocks Qh7
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Alright, I missed the part "play optimally".
Can't we checkmate in two steps? if we move the knight to e6 and the pawn to f8 the pawn becomes whatever u want ...
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after knight to e6, black will move the h6 pawn to provide escape route for the black king. it becomes mate in four not three. although white wins, but it is not the least number of moves as required in the problem.
Answer is 2. Qc4-c8 then moving your horse to g6. The end.
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The key word being 'optimally'. It's not optimal to allow yourself to be checkmated in 2 moves when you can force the inevitable victor into more than 2 moves.
If Qc8 is the first move, Black can force White to 4 moves by moving a pawn away from the king, to create a brief escape.
| Move | White | Black |
| 1 | Qc8 | Ph6 |
| 2 | Ng6+ | Kh7 |
| 3 | f8=N+ | Kg8 |
| 4 | Qe6# |
an alternative, also three moves: 1. Ktg6+ PxKt 2. QxP anything 3. Qh3++
not 3 moves black bishop can move to f6 then h4 to block the white queen on h3
Knight to g6 delays the mate in one move.
it is four moves
Relevant wiki: Chess Puzzles