[blind-chess] Good Article Please Read Carefully was: The Knight's Jump
- From: "R Dinger" <rrdinger@xxxxxxxxxx>
- To: <blind-chess@xxxxxxxxxxxxx>
- Date: Fri, 31 Aug 2012 16:39:04 -0700
Hello All,
Paul's article on the Knight Jump is well worth your time. Take a look and
don't overlook the last section and the explanation of how to avoid a
stalemate in this situation. Or how to turn a loss into a stalemate if you
are losing)!
Richard
----- Original Message -----
From: "Paul Benson" <paul.benson@xxxxxxxxxxxxxxx>
To: <blind-chess@xxxxxxxxxxxxx>
Sent: Thursday, August 30, 2012 5:33 PM
Subject: [blind-chess] The Knight's Jump
Hello all,
This posting contains 4 diagrams. You can jump to the diagrams by
search/find for **, a pair of asterisks
.
The Knight's Jump
.
The Concept
.
The concept of, "The Knight's Jump", came up again recently, in my posting a
solution to Problem WAC094. I thought it might be worthwhile putting a small
article together, with a few further examples of the concept
.
Firstly, the knights jump does not refer to how the knight actually moves.
It instead, is a positional relationship between a queen and an opposing
king. The queen is located on a square, which if she was replaced by a
knight, then that knight would give check to the opposing king. Secondly, in
this article, the queen will always be the white queen, and the opposing
king, will be the black king
.
** Diagram 1, white to move:
.
Short algebraic:
White: Kb1, Qd3, Rc1, Bd2, Nd6, Pg2.
Black: Kh8, Pa7
.
7k/
p7/
3N4/
8/
8/
3Q4/
3B2P1/
1KR5/
.
Yes, a rather unrealistic position, white has an overwhelming material plus.
It is white to play, and mate in 2 moves, in no less than 4 different ways.
The first white move is always the same, so what is the first white move,
permitting 4 subsequent mates on move 2?
.
White closes in for the kill with, 1. Qg6, revealing the concept of the
knight's jump. The queen moves to a square which is as close as possible to
the black kin, without giving check. This proximity controls potential
flight squares around the black king, g7, g8, and h7, now all being covered
by the white queen. The black king has no legal moves, so black must move
the a7 pawn. After black plays, 1. ... a5, the point of restricting the
black king can be observed as white has 4 moves to finish matters. They are,
2. Rc8+, 2. Rh1+, 2. Bc3+, and, 2. Nf7+, all producing mate
.
Once the black king is placed in the straight-jacket of the knights jump
away from the queen, and when the black king is in a corner, it only
requires white to find a move which gives a check where black can neither
block the check, nor capture the checking piece
.
** Diagram 2, white to move:
.
Short algebraic:
White: Kg1, Qd1, Rf1, Be2, Nb5.
Black: Ke8, Pa7
.
4k3/
p7/
8/
1N6/
8/
8/
4B3/
3Q1RK1/
.
Again, unrealistic serious material imbalance. The difference here is that
the black king is centrally placed while being on the edge of the board.
White sets up the knight's jump with, 1. Qd6, but this is not a complete
confinement by the queen, it requires the potential flight square of f7 to
be controlled by the f1 rook. Black now has no legal king move, the f-file
is controlled by the white f1 rook. So after, 1. ... a6, white concludes
matters in any of 3 ways with, 2. Rf8+, 2. Bh5+, and, 2. Nc7+, all being
mate
.
** Diagram 3, white to move:
.
Short algebraic:
White: Ke1, Qd1.
Black: Kf4
.
8/
8/
8/
8/
5k2/
8/
8/
3QK3/
.
Please take a few minutes, and decide how white should proceed from here
.
If called upon to give checkmate with, a king and queen against a lone king,
and the chosen method is going to be the one offered here, there is one very
simple rule to remember. The first check should be checkmate. This means the
queen is going to be very respectful to the opposing monarch. Giving check,
could be considered as assaulting the lone king, and that behaviour will not
be permitted. Instead, this method chooses to restrict the options of the
lone king, using the knights jump straight-jacket as follows
.
White has 3 moves available which create the knight's jump straight-jacket.
They are. 1. Qd3, 1. Qd5, and, 1. Qh5. When a queen is centralised, her
power across a rank, combined with her power up and down a file, effectively
cut the chessboard into 4 sectors. It is most desirable to leave the black
king in a sector with as few as squares as possible, but make absolutely
certain that the king is in a sector of at least 2 squares
.
Variation A: White plays, 1. Qd5, the most favourable move. The black king
is now in a sector of 4 ranks by 4 files, a total of 16 squares.
Furthermore, that sector also contains the white king, which means fewer
moves to deliver mate. The black king, being restricted by the knight's
jump, must now give away either a rank or a file, further reducing his
sector. So, black can try, 1. ... Ke3, and white now creates another
knight's jump with, 2. Qc4, and the black king now has only 1 legal move.
So, 2. ... Kf3, which concedes another file to the white queen. After, 3.
Qd4, the black king is forced to concede even more territory with, 3. ...
Kg3, and yet again the white queen creeps close with, 4. Qe4. Now the black
king must move to the edge of the board with, 4. ... Kh3. Note here, if
instead, 4. ... Kh2, then white has, 5. Qg4, and the black king is now
restricted to only 2 squares, and the white king will approach to support a
queen mate. So, after, 4. ... Kh3, white now breaks the pattern of the
knight's jump restriction with a different restriction. White plays, 5. Qg6,
which confines the black king to the edge of the board, and could be termed
as a Confinement. The end is close now, it is just a matter of the white
king approaching to support mate. The final moves could be, 5. ... Kh4 6.
Kf2 Kh3 7. Qg3+ mate
.
To summarise, the knight's jump is used to force the lone king to concede
territory, with a no-contact dance, until the lone king moves to the edge of
the board. At this point the queen can break the pattern and, should confine
the lone king to the edge, making certain that the now confined lone king
has at least 2 squares for manoeuvring, a precaution against stalemate
.
Variation B: White plays, 1. Qd3, which places the black king in a sector of
5 ranks by 4 files, a total of 20 squares. It should also be obvious that in
this case the restricting process will force the black king up the board.
This means the white king will have to travel further than in Variation A to
support mate. Play could go, 1. ... Ke5 2. Qc4 Kf5 3. Qd4 Ke6 4. Qc5 Kf6 5.
Qd5 Ke7 6. Qc6 Kf7 7. Qd6 Kg7 8. Qe6, and the no-contact dance has had the
white queen and black king, take a zig-zag route up the board. The black
king must now move to the edge, for example, 8. ... Kh7. Now white breaks
the pattern of the knight's jump, to confine the black king to the edge
with, 9. Qg4, leaving the black king with 3 squares on which to shuffle. The
white king will march to f6, to support mate, delivered in 6 moves
.
Variation C: White plays, 1. Qh5, giving the black king a sector of 7 files
by 4 ranks, a total of 28 squares. However, the white king is also in the
sector, so the mobility of the black king will be considerably hindered.
Note: In this example the white king could easily join in much earlier, and
not let the black king run into the queenside. However, this is a
demonstration of how a queen on her own can drive a lone king across the
board. Play could continue, 1. ... Ke4 2. Qg5 Kf3 3. Qh4 Ke3 4. Qg4 Kd3 5.
Qf4 Kc3 6. Qe4 Kb3 7. Qd4 Kc2 8. Qe3 Kb2 9. Qd3 Ka2, and white now confines
the black king with, 10. Qb5, and mate will follow in 3 moves after the
white king reaches the c-file. The c3 square being the square to support
mate, irrespective of the location of the black king
.
So, are there any problems with utilising the knight's jump? Yes, care must
be taken once the lone king has been politely requested to retire to the
edge of the board. There are 2 patterns to avoid, given below
.
** Diagram 4, white to move:
.
Short algebraic:
White: Kg5, Qc6.
Black: Kf7
.
8/
5k2/
2Q5/
6K1/
8/
8/
8/
8/
.
Variation A: White plays, 1. Qd6, and black plays for a blunder from white
with, 1. ... Ke8. The game would last longer had black headed slowly for the
corner. Now, with the black king on the edge of the board, white should of
course immediately confine the black king with, 2. Qc7, with a quick mate to
follow. However, should white break this rule, and instead bring the king
into the action with, 2. Kf6, then all the hard work is thrown away, as the
black king is in stalemate. So, when the opportunity to confine the lone
king to the edge of the board with the queen arises, immediately take it,
providing the confined lone king is being given at least 2 squares in which
to shuffle
.
Variation B: Again, white correctly plays, 1. Qd6, and this time, having
learned the lesson from Variation A just given, white is going to play the
knight's jump restriction for all it is worth. Black plays, 1. Ke8, but
white is not falling for that one again. Play continues with, 2. Qc7 Kf8.
Now white should approach with the king to support mate, however, this is to
show what happens when a good idea is taken too far. So, 3. Qd7 Kg8 4. Qe7
Kh8. Now the black king is reduced to 2 squares, the white king should
approach. However, what happens if the white queen becomes over-zealous
about all the fun to be had with the knight's jump no-contact dance? Well,
5. Qf7, would be consistent here, and would also produce another stalemate.
Yes, the queen placed a knight's jump from an opposing king in a corner, is
inflicting a stalemate all on her own. So, the confined king must always be
given at least 2 squares in which to shuffle, while the attacking king
approaches to support mate
.
Paul Benson.
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