Plachutta
Encyclopedia
The Plachutta is a device found in chess problem
Chess problem
A chess problem, also called a chess composition, is a puzzle set by somebody using chess pieces on a chess board, that presents the solver with a particular task to be achieved. For instance, a position might be given with the instruction that White is to move first, and checkmate Black in two...

s: a white piece sacrifices itself on a square where it could be captured by one of two similarly-moving black pieces (for example, a bishop
Bishop (chess)
A bishop is a piece in the board game of chess. Each player begins the game with two bishops. One starts between the king's knight and the king, the other between the queen's knight and the queen...

 and a queen
Queen (chess)
The queen is the most powerful piece in the game of chess, able to move any number of squares vertically, horizontally, or diagonally. Each player starts the game with one queen, placed in the middle of the first rank next to the king. With the chessboard oriented correctly, the white queen starts...

 moving along a diagonal, or two rook
Rook (chess)
A rook is a piece in the strategy board game of chess. Formerly the piece was called the castle, tower, marquess, rector, and comes...

s) moving along a different line; whichever black piece captures, it interferes with the other. Plachutta theme is named by Joseph Plachutta
Joseph Plachutta
Joseph Plachutta, also Josef Plachutta or Josip Plahuta was a Slovene descent chess problemist and chess player, known for his famous problem with Plachutta theme....

 (1827–1883).

The Plachutta is related to a number of other problem themes: it can be regarded as a Würzburg-Plachutta brought about by a white sacrifice on the critical square (a Würzburg-Plachutta itself being a pair of Holzhausen
Holzhausen
Holzhausen may refer to:Places*in Germany:**Holzhausen, Saxony-Anhalt, a municipality in the district of Stendal, Saxony-Anhalt**Holzhausen an der Haide, a municipality in the Rhein-Lahn district, Rhineland-Palatinate...

 interferences); or it can be thought of as a Novotny with similarly-moving (rather than differently-moving) black pieces involved (a Novotny itself being a Grimshaw
Grimshaw (chess)
A Grimshaw is a device found in chess problems in which two black pieces arriving on a particular square mutually interfere with each other. It is named after the 19th century problem composer Walter Grimshaw....

 brought about by a white sacrifice on the critical square). It can also be compared to the anti-Bristol, in which two similarly-moving black pieces interfere with each other along the same line.
The problem to the right is a relatively simple example by William Shinkman, published in White Rooks, 1910. It is a mate in three (white moves first and must checkmate black in three moves against any defence). The key (first move of the solution; see chess problem terminology
Chess problem terminology
This is a list of terms used in chess problems. For a list of unorthodox pieces used in chess problems, see fairy chess piece. For a list of terms used in chess is general, see chess terminology.- A :*Actual play - see post-key play....

) is 1.d5. Examining the initial position reveals why this works: white would like to play either 1.Ra8 or 1.Rg8, but the former is prevented by black's bishop and the latter is prevented by black's queen. 1.d5 blocks the paths of both black pieces to these squares, and whichever black piece takes the pawn interferes with the other and has to defend against both threats itself (to use chess jargon, it becomes overloaded
Overloading (chess)
Overloading is a chess tactic in which a defensive piece is given an additional defensive assignment which it cannot complete without abandoning its original defensive assignment.-Example:...

). So, if 1...Qxd5 white can play 2.Ra8+ Qxa8, when the queen is deflected from her defence of g8, allowing 3.Rg8#, while if 1...Bxd5 white can play 2.Rg8+ Bxg8, deflecting the bishop from defence of a8, allowing 3.Ra8#.
To the right is another relatively simple example, but this time it is two rooks, rather than bishop and queen, involved in the interferences. The problem, by D. J. Densmore, published in the Gazette-Times, 1916, is another mate in three. The key is 1.Nb7, which interferes with both rooks and so threatens both 2.Rh7# and 2.Rb1#. Black can defend with Raxb7, but this overloads the capturing rook, so white can play 2.Rb1+ Rxb1 3.Rh7#. The other capture is similar: 1...Rbxb7 2.Rh7+ Rxh7 3.Rb1#. Whichever rook captures, it interferes with the other and becomes overloaded, having to defend against two threats on its own.
A more sophisticated modern example is the award-winning mate in four problem to the right, by Aleksandr N. Pankrat'ev and Josip Varga, which was published in Sahovski Glasnik in 1991 and won 1st Prize. White begins with 1.e3, adding protection to d4 and threatening 2.Rc5#. Black's two main defenses are the two captures on e3, but each one allows a different Plachutta interference by White on move 2. If 1...Rxe3, White plays 2.f4!, a Plachutta interference with the queen and bishop: 2...Qxf4 allows 3.Nxe3+ Qxe3 4.Nxe5# and 2...Bxf4 allows 3.Nxe5+ Bxe5 4.Nxe3#. If 1...Bxe3, White plays 2.Bb3+!, a Plachutta interference with the two black rooks: 2...Rbxb3 allows 3.Nxe3+ Rxe3 4.Nb6# and 2...Raxb3 allows 3.Nb6+ Rxb6 4.Nxe3#.
Although the term Plachutta is confined to the world of chess problems, not being used in a wider chess context, the underlying Plachutta pattern does occasionally (though rarely) appear in an actual game. One example is to the right, a position which occurred in a 1914 game between Siegbert Tarrasch
Siegbert Tarrasch
Siegbert Tarrasch was one of the strongest chess players and most influential chess teachers of the late 19th century and early 20th century....

(with white) and a team of opponents consisting of Davide Marotti (who became the champion of Italy in 1921), E. Napoli, de Simone, and del Giudice. In the diagrammed position, the black queen defends against Qb7 and the rook on c8 defends against Rxc5. Tarrasch played 31.Bc7!, a Plachutta interference after which black cannot maintain control over both b7 and c5 (black actually resigned after this move). If 31...Rxc7 the rook is overloaded, having to look after both the key squares: 32.Qb7+ Rxb7 and the rook is deflected from defence of c5, allowing 33.Rxc5#. If instead 31...Qxc7 it is the queen which is overloaded: 32.Rxc5+ Qxc5 deflects the queen from defence of b7, allowing 33.Qb7+ Kxa5 34.Ra1#.

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