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Statistics: Posted by alexeioganesyan — 16 August 2014, 2:41 pm

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1 Re1 Bg2 2 Qh4#

1...Kxe1 2 Qd2#

Apart from Kxe1 (for which White has the mate Qd2), Black's only options are with the bishop. Random moves fail to meet Qg1.

Black corrections: Bg2 parries by closing the line the queen needs to move along.

Aspa #2-

1 Bg6 Ne5 2 Qb6#

1...Ne3 2 Qf6#

Black's only options are with the knight. Random moves fail to meet e3.

Black corrections:

Ne5 parries it by closing the line the queen guards along.

Ne3 parries it by blocking the pawn.

Mansfield #2-

1 Qe2.

Primary Black error and White threat: 1 Qe2 threatens 2 Qe7, which is mate if Black makes a random move of the rook or bishop.

There is also the mate

1...e6/e5 2 Rxd8#

Primary black correction: Black can refute White's threat of 2 Qe7# by moving the knight, opening a diagonal so that bBa3 guards e7.

Secondary Black error and White threat: If Black moves the knight, Black unguards d7. White now threatens 2 Qb5, which is mate if Black makes a random move of the knight. (Qb5 is not a primary threat because Nd7 parries; Qb5 is mate only if Black moves the knight, and not always then.)

Secondary black correction: Black can refute both White threats with 1...Nd3 (closing the line the queen needs to move along) or 1...Nd7 (closing the line the queen needs to guard along).

Tertiary Black error: Both these Black moves interfere with the bRd8 and thus unpin the wBd5, thus leading to the mates

1...Nd3 2 Bc6#

1...Nd7 2 Bf7#

Mladenovic #3-

1 Ra5

Primary Black error and White threat: 1 Ra5 threatens 2 Ra4+ Nb4 3 Rxb4.

Primary Black correction: Black can refute White's threat of 2 Ra4+ by moving the bishop, creating a king-flight at d5.

Secondary Black error and White threat: Black moving the bishop opens the fifth rank so that the wRa5 guards e5. White now threatens

2 Qc2+ Kxd4 3 Nf5

2 ... Kb4 3 Rxa4#

which is mate if Black makes a random move of the bishop.

Secondary Black correction: Black can refute both White threats with

1 ... Be4 (guarding c2),

1 ... Be6 (guarding f5) or

1 ... Bc6 (guarding a4).

Solution-branch A

Tertiary Black error: 1...Be4 interferes with the bRe1, unguarding e6, allowing 2 Be6+ Bd5 3 Bxd5#.

Solution-branch B

Tertiary Black error: 1...Be6 interferes with the bRe1, unguarding e8.

Tertiary White threat: 2 Nxe8 (threat 3 Nd6#).

Quaternary Black error: Random Black moves allow 3 Nd6#.

Quaternary Black correction: 2...Nc5 (interfering with the wRa5 and making a Black king-flight at d5) 3 Rxc5#.

Solution-branch C

Tertiary Black error: 1...Bc6 obstructs the sixth rank.

Tertiary White threat: 2 Nc8 (threat Nb6#).

Quaternary Black error: Random Black moves allow 3 Nb6# because Re6 doesn't guard b6.

Quaternary Black correction: 2 ... Rb1 (guarding b6 along the file, not the rank) 3 Be2#.

To summarize:

1 Ra5 (threat 2 Ra4+ Nb4 3 Rxb4#)

1...B~ 2 Qc2+ Kxd4 3 Nf5#

2...Kb4 3 Rxa4#

1...Be4 2 Be6+ Bd5 3 Bxd5#

1...Be6 2 Nxe8 (threat 3 Nd6#) Nc5 3 Rxc5#

1...Bc6 2 Nc8 (threat Nb6#) Rb1 3 Be2#

Statistics: Posted by garykevinware — 14 August 2014, 12:16 am

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Black Correction- A random move of a black piece, a primary defense, carries a harmful effect, called 'primary error' (or 'general error') which White can utilize (to mate) with the secondary threat (or a contingent threat). However, the same black piece can play so as to compensate the primary error and prevent the secondary threat, but this corrective move (or simply 'correction') has a new disadvantageous effect, a secondary error which White can utilize.

Samuel Loyd Musical World 1859 #2

The following problem is one of the first examples with two corrections of the black Knight.

Rosario Aspa Illustrated London News 1845 #2

Tertiary Black Correction- As all possible moves of one piece carry the same removal effect as its random move, raising the play to higher degrees is possible only by gradual accumulation of (line-)arrival weaknesses in its corrective moves. The only one arrival weakness can be repeated by the same piece in two parallel variations, and that is the interference on the same line.

Comins Mansfield Australian Meredith Tourney 1928 #2

Quarternary Black Correction- The chess geometry does not allow one piece to close the line of another in the narrow space of a two-mover. However, in one move longer problems, it is possible to extend the action of a line-piece along the bent line, thus providing more spots for arrival of another piece to it.

Miodrag Mladenovic Olympic Tourney 2009-10 #3

9 points for sending me a complete variation to each problem, at garykevinware@yahoo.com , by next Wednesday.

Statistics: Posted by garykevinware — 6 August 2014, 11:42 pm

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Try 1 Kf2+ Rxa1!, so let's try moving a bishop. Moving the h7 bishop first, fails to Rxh8, creating a king-flight at h2, thus destroying both White's mates. So White must move the h2 bishop. If Black then moves the rook along the a-file, threatening to interpose, White moves the h7 bishop to the same rank as Black's rook, to interfere with it. But Black can finesse this rook-move, with Ra7; when the h7 bishop moves, it must move to a different rank, and it fails to stop Rh7. So, to anticipate this, White must move 1 Bc7. Moreover, 1 Bc7 Rxa1+ 2 Bb1# works.

Try

1 Bb8 (thr h7B~) Ra7!

1 2B almost anywhere (thr Bg8) Ra7!

1 Qxa8? Kxh2!

So, 1 Bc7! (thr Bg8)

1 ... Ra6 2 Bg6#

1 ... Ra5 2 Bf5#

1 ... Ra4 2 Be4#

1 ... Ra2 2 Bc2#

1 ... Rxa1+ 2 Bb1#

1 ... Rxh8 2 Kf2#

We have White correction with the h2 bishop. Does Black's need to take care to move his rook to a7 to be able to interpose count as Black correction? Or perhaps unsuccessful Black tries to refute a White try don't count?

My response to that question will be the upcoming Gary's Gems post on Black Correction.

Here is a link to the problem: http://www.yacpdb.org/?id=4436

Statistics: Posted by garykevinware — 6 August 2014, 11:41 pm

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Jiri Chocholous Prager Zeitung 1879 #2

2 points for sending me a complete variation, at garykevinware@yahoo.com , by next Wednesday.

Statistics: Posted by garykevinware — 30 July 2014, 10:17 pm

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White has 10 options. 9 lose. Only one wins.

1 Nc4? Rd8 {R~8}; Black gets to check; White must move his king and unguard wPa7; ...Kxa7 and Black wins with RP v N.

1 Nd5! R~ 2 Nxc7#; 1 ... c~ 2 Nb6#

White has 10 options. 9 lose. Only one wins.

1 Ne1?/Ng1? Nb3+! 2 Kd1 Kb1 3 Ke2 a1=Q and Black wins at move 11.

1 Nd2? Nb1/Nb5 2 Nf3 Nb3+! 3 Kc2 Nc5 4 Kc1 Na3 5 Nd4 Nd3+ 6 Kd2 Kb2 7 Kxd3 a1=Q and Black wins at move 18.

1 Nd4! 3N~ 2 Nc2#; 1 ... 5N~ 2 Nb3#

Statistics: Posted by rosefairy — 30 July 2014, 8:47 am

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madoldman wrote:

I am looking for a directmate problem (ideally, mate in 2) with the following feature:

all first moves by white (except, of course, the mainline solution) lead to a forced win by Black (or maybe a draw.)

Cheers!

Welcome, madoldmanI am looking for a directmate problem (ideally, mate in 2) with the following feature:

all first moves by white (except, of course, the mainline solution) lead to a forced win by Black (or maybe a draw.)

Cheers!

It might be a bit obvious, but

1 Ne4! N~ 2 Nc3#

and if White does anything else, Black mobilises his queen.

If the black queen out of play in that first problem was a bit inelegant, here's a 6-man kindergarten problem

Try 1 a3? a4 2 Kd~ and Black frees his king

1 a4! b5 2 axb5#

In that first problem, White has 11 options; in the second, 6. If you like the idea of White having many options, how about these?

White has 15 options. One wins in 2. 14 lose.

Try 1 Qa~? b1=Q+!

1 Kd~? b1=Q+/Ka2!

1 Qb3! b1=any 2 Qxb1#

White has 19 options. One wins in 2. 3 draw. 15 lose.

Try 1 Rd4+? Nd3! 2 Rxd3"!" (White has already blundered one half-point; this is the only move that doesn't blunder the other) Kc1 {Ke1} 3 Rxc3 Kd1! 4 Rc~ c1=Q/R/N (c1=B? 5 Kd3! wins) 5 Rxc1 Kxc1 draw

1 Rf4?/Rh4? Nd3! 2 Kxd3"!" c1=N+! drawing

1 Rg4? Ne2! and Black wins at move 11

1 Ra1! Ke1 2 Rxc1#

Statistics: Posted by rosefairy — 29 July 2014, 3:41 pm

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Statistics: Posted by garykevinware — 29 July 2014, 3:09 pm

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Cheers!

Statistics: Posted by madoldman — 29 July 2014, 1:40 am

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