Lev Loschinski, Two-mover, Black Arrival Correction

Lev Loschinski was a master of composition. His name is pre-eminent like Comins Mansfield for the two-mover. However, he was equally great in the three-mover, in the modern as well as the strategic, discovered various new artisitic touches such as the Loschinski "magnet". Here, we see a elegant and spare setting for a two-mover featuring 'arrival correction', a term connoting the mechanism for separating the white mates, as explained below.

After the key (click on the 1.?), a random Black piece needs to arrive on d4 to prevent the threat (>2.Qxa7). However arrival of a powerless Black piece allows 2.Qxe2 mate. However, since the Black piece that arrives has powers to move and is not just a square-occupier, new mates are required and enforced thus:

1...d4 2,Qxe2? d3!! Therefore 2.Bc4# (Black pawn has interfered with the fourth rank)

1...fSd4 2,Qxe2 Sxe2 Therefore 2.Ra3# (Black line-opening third rank, valve closing 4th)

1...eSd4 2,Qxe2?? Therefore 2.Qa2# (Black line-opening third rank, valve closing 4th)

1...Bd4 Therefore 2.Qxe2# (Black bishop has interfered with the fourth rank)

1...Rd4 (Completing the Grimshaw (defintion: Two variations in which Bishop and Rook interfere with the other on the same square)) 2.Qxe2? Rc4, Therefore Rh6#(Black rook has vacated the h file (line-clearance) while BB's control of h6 has been interfered with, this is Grimshaw)

Tries in two-mover, "schnittpunkt" theme

In set play, we have 1...Sd6 (a self-block) 2.Sd3 mate (it is OK for White to interfere with the d-line because of Black's self-block on d6. White chooses to close exactly the same line on which Black piece lies like an X-ray).

The pair variation in set play is 1...Sf6, 2. Sg6 mate (White closing the sixth rank, since f6 is a self-block)

The theme of schnittpunkt is the a point where two lines intersect. Let us try 1. Bb1 (or 1.Bc2).Threat is Qe4. This Try crosses the critical square d3. All mates are set except for 1....Sd6! (Now the set mate attempt failes 2. Sd3 dis ch? 2 Kf5!! White is closing his bishop's control of f5 (which is not ok) at the same time he is closing the d file (which is ok).

The pair try is 1.Bh7. Again threat is Qe4. Black this time defends with 1...Sg6! Now white's set mate 2. Sg6 dis ch is not mate, since he is once again closing his bishop's control of f5 (2...Kf5!!), not OK!, whereas closing the sixth rank was ok because of the self-block.

The Key was 1.Kf3! Threat 2.Qh5

1...Sd6 2.Sd3

1...Sf6 2.Sg6

1..R(f,g)8 2.Rxe6

1...Se7 2.Rxe6

1...B(g1->any) 2.Qa1#

In other notes, these two published an Original joint problem in 1955 in "The Hindu", a newspaper which ran a chess problem column that was, after my Rice, Matthews, Lipton, a bit of a Indian weekend entertainment some decades ago. However, 1955 was even earlier than my time....

Black unpins White

Arnoldo Ellerman (12.01.1893-21.11.1969), an Argentine, was a prolific composer of two-movers. He showed many Black line-themes (interference and shut-offs) in the Good Companion problem folders. Here, the theme is Black unpinning White, not out of kindness, but to avert a threat. This will cause another defect in the Black position, allowing precisely separated mates.

1. Qh1! [ Threat >2. Qf3#]

1. ... Rd4 Interference with dark sq bishop allowing 2. Sf6#

1. ... Rc3 Interference with dark sq bishop allowing 2. Sf6#

1. ... Rd3 Interference unpin of white rook 2.Shut-off (of Rd3), discovered mate 2.Re3#

1. ... Bxe2+ 2. Bxe2# is not thematic

1. ... Rc4 Interference unpin of white rook 2.Shut-off (of Rc4), discovered mate 2.Re4#

1...Bb7 Withdrawal unpin of white rook 2.Shut-off (of Bb7), discovered mate 2.Re4#

1. ... Bc8 Withdrawal unpin of white rook 2.Shut-off (of Bc8), discovered mate 2. Re6#

1. ... Kg4 (a flight granted by key) 2. Qf3#

The beauty of the problem is the combination of the two ways in which a line-piece may be unpinned, by interference and by withdrawal. It will pay for newcomers to play over these beautiful variations.

Cross-checks, King flights, in the two-mover

Click on the 1.? after you have tried to solve it.

The main threat with the key is 2.Qxe4 mating, (the key paves the Queen's control on the e6 square initially obstructed). However, the main play is that the key sets up a surprising strong line of attack on the white-king, allowing the Black king to give as many as three discovered checks. These may be termed a royal battery, the King being the firing piece and the queen giving white check from the rear. For each, White's checkmating reply is separately forced as we shall see soon. This sequence where B gives W check, and W checkmates right back is called a cross-check. (As many as five cross-checks have been shown in a single problem, a "task".)

If 1...Ke6 ch, 2. Sc5 is dbl ch and mate. The knight blocks the discovered check of black, arriving on c5, it discovers double check from the light-sq bishop, and the king cannot move to the seventh rank, since the knight had also discovered the W Q's guard of e7!

If 1...Kg6 ch, 2.Se5 ch mates, (e5 interposes the check), g7 is not a run-out for His Majesty, since W Q's guard on g7 has been discovered, and B does not have QxS which is illegal(!) since Her Majesty is pinned upon this King flight by WR on g2.

If 1...Kxf4 ch, 2.Sd5 dbl ch mates (d5 interposes the check), it is dbl ch, discovered from the Rook battery down the f-file this time, and e3 square is diabolically covered by the checking Knight.

Slightly less thematic, but still cute, is the last variation 1...Qxf4, not a cross-check or a King flight. Now 2.Sb8 mates. The king cannot run to f4 on account of the "self-block", and the action to prevent the black rook line on the eighth rank is called a shut-off mate.

Sam Loyd, puzzle king

The first thing you do in a "mate in two" problem, is the examine the "set" play. This means you pretend it is Black to move first, and you find checkmate moves for White

Set Play:

1. ... d5 2. Sc5#

1. ... b2, Sb4/a3/e3/e1 2. Q(x)b4#

1. ... Ra3/b2 2. S(x)b2#

In this problem, every legal black move has a White mate provided in the initial position. Such a position is called a "block". Sometimes, to preserve the character of a block problem, you try to find a quiet White move, that keeps Black in this trouble. Can we do that here? Let us see. If Bd1 moves, Black can now play b2, and there is no pin on the knight(S) at c2, no mate Qb4. If Bxc2, Sxc2. Strong checking moves by the Queen are useless, since 1.Qa7ch? Kb5 and the king escapes. The White rook cannot move gainfully. It releases the e-pawn 1...e5+ by Black would not be nice. How do we find a quiet move?

Some more terminology for future use. Neither the Black p at b3 nor S at c2 are pinned, but they can be said to be half-pinned. A great English composer Comins Mansfield, made many problems where the main line of play uses halfpins. Entire books have been written about problems with half-pins "Het Half-pin thema" in Dutch.

Have you solved it yet?

Sam Loyd was one tricky guy. The key move does not preserve the quiet. It introduces a threat. Such problems with a block in the set play and a threat in the "key" (the solution's first move) are called "block-threat" problems and are both rare and difficult to solve. Here the key is 1.Sa3! (>2. Threat Qa7#) (By covering b5, the threat is set up for the mate.) Here are the variations

1. ... Kxa3 2. Qa5/a7#

1. ... b2, Sb4/xa3 2. Q(x)b4#

1. ... Rxa3 2. Sb2#