Retrograde edits
This commit is contained in:
@@ -127,10 +127,6 @@ Mate the king in one move. \par
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\pagebreak
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\pagebreak
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% Sherlock, a question of survival
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% Sherlock, a question of survival
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\problem{An empty board}
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\problem{An empty board}
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\difficulty{2}{5}
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\difficulty{2}{5}
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@@ -161,42 +157,6 @@ There is one more piece on the board, which isn't shown. What color square does
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\pagebreak
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\pagebreak
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% Sherlock, another monochromatic
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\problem{The knight's grave}
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\difficulty{3}{5}
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In the game below, no pieces have moved from a black square to a white square, or from a white square to a black square.
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The white king has made less than fourteen moves. \par
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Use this information to show that a pawn was promoted. \par
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% spell:off
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\manyboards{
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ke8,
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Pb2,Pd2,
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Ke1
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}
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% spell:on
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\begin{solution}
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Knights always move to a different colored square, so all four missing knights must have been captured on their home square.
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What pieces captured them?
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\vspace{2mm}
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We can easily account for the white knights and the black knight on G8, but who could've captured the knight from B8?
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The only white pieces that can move to black squares are pawns, the Bishop (which is trapped on C1), the rook (which is stuck on column A and row 1), or the king (which would need at least 14 moves to do so).
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\vspace{2mm}
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If this knight was captured by a pawn, that pawn would be immediately promoted. If it was captured by a piece that wasn't a pawn, that piece must be a promoted pawn.
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\end{solution}
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\vfill
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\pagebreak
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% Arabian Knights, intro (given with solution)
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% Arabian Knights, intro (given with solution)
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@@ -372,4 +332,122 @@ Which bishop was it, and what did it capture? \par
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\end{solution}
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\end{solution}
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\vfill
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\vfill
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\pagebreak
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\pagebreak
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% Sherlock, appendix
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\problem{Moriarty's first}
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\difficulty{3}{5}
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No captures have been made in the last four moves. \par
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It is White's move. What was the previous move?
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% spell:off
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\manyboards{
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Bc8,
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pg6,
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Pg5,kh5,
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Pd4,Qg4,Bh4,
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pd3,
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Pd2,Be2,Bg2,
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Nc1,rd1,Ne1,Kf1,Qg1,Rh1
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}
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% spell:on
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\begin{solution}
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To see what the position was four moves ago,
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move the Black queen to E4, the knight on E1 to F3,
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the Black bishop to E1, and the White bishop on C8 to H3.
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The following sequence of moves brought the game to the present position:
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\begin{itemize}
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\item bishop to c8, check
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\item bishop to h4, check
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\item knight to e1, check
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\item queen to g4.
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\end{itemize}
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This is the only way the present position could have arisen,
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so Black's last move was with the queen from E4 to G4.
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Try any other last move, and you will find it impossible to play back three more moves.
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\end{solution}
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\vfill
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\pagebreak
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% Sherlock, appendix
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\problem{Moriarty's second}
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\difficulty{3}{5}
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Neither the White king nor queen has moved
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during the last five moves, nor has any piece
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been captured during that time.
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What was the last move?
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% spell:off
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\manyboards{
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kh8,
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Kg6,Bh6,
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pa4,
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Qa2
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}
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% spell:on
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\begin{solution}
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Put the Black pawn on A7, the Black king on G8, remove the
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White bishop, and put a White pawn on d5; this was the position
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five moves ago. The following sequence of moves brought the
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game to its present position:
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\begin{itemize}
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\item White: P-d6
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\item Black: K-h8
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\item White: P-d7
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\item Black: P-a6
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\item White: P-d8 = B
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\item Black: P-a5
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\item White: B-g5
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\item Black: P-a4
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\item White: B-h6
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\end{itemize}
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\end{solution}
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\vfill
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\pagebreak
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% Sherlock, appendix
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\problem{Moriarty's third}
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\difficulty{3}{5}
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No pawn has moved, nor has any piece been
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captured in the last five moves. \par
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The Black king has been accidentally
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knocked off the board. \par
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On what square should he stand?
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% spell:off
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\manyboards{
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rh8,
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pa7,pb7,pc7,pd7,pe7,Kf7,pg7,Ph7,
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Pg6,
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na2
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}
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% spell:on
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\begin{solution}
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The only way to avoid a retrograde stalemate for White is by
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placing the Black king on C8. Black's last move was with
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the rook from D8, White's move before that was with his
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king from G8, and Black's move before that was to castle.
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\end{solution}
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\vfill
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\pagebreak
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@@ -169,16 +169,156 @@ White to move. Which side of the board did each color start on? \par
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% Sherlock, another monochromatic
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\problem{Monochromatic}
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\difficulty{4}{5}
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In the game below, no pieces have moved from a black square to a white square or from a white square to a black square.
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The white king has made fewer than fourteen moves. \par
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Use this information to show that a pawn was promoted. \par
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% spell:off
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\manyboards{
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ke8,
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Pb2,Pd2,
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Ke1
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}
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% spell:on
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\begin{solution}
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Knights always move to a different colored square, so all four missing knights must have been captured on their home square.
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What pieces captured them?
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\vspace{2mm}
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We can easily account for the white knights and the black knight on G8, but who could've captured the knight from B8?
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The only white pieces that can move to black squares are pawns, the Bishop (which is trapped on C1), the rook (which is stuck on column A and row 1), or the king (which would need at least 14 moves to do so).
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\vspace{2mm}
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If this knight was captured by a pawn, that pawn would be immediately promoted. If it was captured by a piece that wasn't a pawn, that piece must be a promoted pawn.
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\end{solution}
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\vfill
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\pagebreak
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% Sherlock, another question of location
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\problem{Superposition}
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\difficulty{4}{5}
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A white pawn is missing; it is either on F2 or G2. \par
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Where is it?
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% spell:off
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\manyboards{
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ke8,rh8,
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pa7,pf7,pg7,
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pa6,pb6,
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pb5,
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Pa4,Pb4,Pc4,
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pa3,
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Pa2,Pb2,
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Ke1
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}
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% spell:on
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\vfill
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\pagebreak
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% Sherlock, another question of location
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\problem{Possibility}
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\difficulty{4}{5}
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Show that black can castle to either side. \par
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We know the following:
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\begin{itemize}
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\item White started the game missing one rook.
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\item White has not moved either knight
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\item No promotions have been made
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\item White's last move was from E2 to E4.
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\end{itemize}
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% spell:off
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\manyboards{
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ra8,ke8,rh8,
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pa7,bb7,pc7,pd7,pf7,pg7,ph7,
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nc6,nh6,
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pe5,qg5,
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bb4,Pe4,
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Pb2,Pc2,Pd2,Pf2,Pg2,Ph2,
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Nb1,Bc1,Qd1,Ke1,Bf1,Ng1,Rh1
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}
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% spell:on
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\vfill
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\pagebreak
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% Sherlock, little exercise 2
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\problem{Kidnapping}
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\difficulty{4}{5}
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On which square was the White queen captured?. \par
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% spell:off
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\manyboards{
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ra8,qd8,ke8,ng8,rh8,
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pa7,pb7,pc7,pe7,pf7,ph7,
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nc6,pe6,ph6,
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Pb3,
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Na2,Pb2,Pc2,Pd2,Pe2,Pf2,Pg2,Ph2,
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Ra1,Ke1,Rh1
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}
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% spell:on
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\begin{solution}
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White is missing a queen, both bishops, and one knight. \par
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The black pawns on E6 and H6 account for two captures.
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\vspace{2mm}
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Neither white bishop could've been captured by these pawns,
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since both are trapped by their pawns. Thus, these black pawns must have captured a queen and a knight.
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\vspace{4mm}
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The white pawn on B3 must have captured a black bishop. \par
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The white queen got onto the board through A2. \par
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Therefore, the pawn on B3 made its capture before the queen escaped,
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and the black bishop was captured before the white queen.
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\vspace{4mm}
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Similarly, the bishop from C8 must have been
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captured on B3 after the capture on E6, since it
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got on the board through D7.
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\vspace{4mm}
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The capture on E6 was made before the capture on B3 (black bishop),
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which was made before the white queen was captured.
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Therefore, the white queen was not captured on E6, and must
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have been lost on H6.
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\end{solution}
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\vfill
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\pagebreak
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% Arabian Knights 4
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% Arabian Knights 4
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\problem{A missing piece}
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\problem{A missing piece}
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\difficulty{4}{5}
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\difficulty{6}{8}
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There is a piece at G4, marked with a $\odot$. \par
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There is a piece at G4, marked with a $\odot$. \par
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@@ -2,7 +2,7 @@
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% Arabian Knights 5
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% Arabian Knights 5
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\problem{The hidden castle}
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\problem{The hidden castle}
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\difficulty{7}{7}
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\difficulty{8}{8}
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There is a white castle hidden on this board. Where is it? \par
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There is a white castle hidden on this board. Where is it? \par
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None of the royalty has moved or been under attack. \par
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None of the royalty has moved or been under attack. \par
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@@ -30,7 +30,7 @@ None of the royalty has moved or been under attack. \par
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% Arabian Knights 6
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% Arabian Knights 6
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\problem{Who moved last?}
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\problem{Who moved last?}
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\difficulty{7}{7}
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\difficulty{8}{8}
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After many moves of chess, the board looks as follows. \par
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After many moves of chess, the board looks as follows. \par
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Who moved last? \par
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Who moved last? \par
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@@ -58,7 +58,7 @@ Who moved last? \par
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% Arabian Knights 3
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% Arabian Knights 3
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\problem{The king in disguise}<kingdisguise>
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\problem{The king in disguise}<kingdisguise>
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\difficulty{7}{7}
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\difficulty{8}{8}
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The white king is exploring his kingdom under a disguise. He could look like any piece of any color.\par
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The white king is exploring his kingdom under a disguise. He could look like any piece of any color.\par
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Show that he must be on C7.
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Show that he must be on C7.
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@@ -119,7 +119,7 @@ Show that he must be on C7.
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% Arabian Knights 3
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% Arabian Knights 3
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\problem{The king in disguise once more}
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\problem{The king in disguise once more}
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\difficulty{5}{7}
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\difficulty{5}{8}
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The white king is again exploring his kingdom, now under a different disguise. Where is he? \par
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The white king is again exploring his kingdom, now under a different disguise. Where is he? \par
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\hint{\say{different disguise} implies that the white king looks like a different piece!}
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\hint{\say{different disguise} implies that the white king looks like a different piece!}
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Reference in New Issue
Block a user