Sub-metamorphosis
As underpromotion is known in chess , the conversion of a farmer on the opponent's home row in an inferior figure as the lady - that is, in Tower , runners or jumpers .
Motivation and occurrence
Conversions in a Springer rare in practical batches up occasionally to a chess to offer - usually combined with a fork or as part of a Matt combination. On the other hand, serious conversions into rooks and especially bishops in a normal game are extremely rare; they can serve to avoid an opposing stalemate . Sub-metamorphosis is a popular motif in chess composition . In addition to avoiding stalemate, there is also the motivation to use a sub-transformation for your own stalemate as a remischance .
Examples
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White to move wins only by transforming it into a knight:
1. e7 – e8S +! with knight fork followed by mating with bishop and knight . The conversion into a queen 1. e7 – e8D? after Qc7 – f7 + leads to an exchange of queens and a draw .
Amusements in Chess, 1845
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If immediately converted into a queen, Black would be stumped . 1. Kc6 – d7 results in an easy win, but checkmate does not occur until move 7. The sub-transformation into a rook, on the other hand, leads to pressure and mate :
1. c7 – c8T! Ka7 – a6
2. Rc8 – a8 #
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White only wins by
transforming himself into a bishop on c8: 1. c7 – c8L! Black can now only move the bishop; however, it doesn't matter where he moves it: 1 ... B ~ 2. Nc5 – d7 L ~ 3. Bc8 – b7 # . On the other hand, a change to a rook or queen would result in an immediate stalemate because the black king cannot move himself and his bishop is tied on b8. A transformation into a knight is not enough - with the right black counterplay - for a win either.
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Babushkin-Postnikow, long-distance game, USSR 1969/70
One of the rare sub -metamorphoses into a knight without a check requirement that can be found in practical games: 1. e7 – e8S! and Black cannot prevent the following perpetual check on c7 and b5.
1932
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Only by transforming into a rook can White bring about his own stalemate and avoid defeat:
1. a8T! h2
2nd Ra3! h1D
3. Ka4 + d3
4. b3
Black cannot prevent the stalemate.
Further examples of sub- metamorphoses can be found in the studies by Benkő , Saavedra , Vitali Halberstadt , Gorgijew and Selesnjow . Pogosjanz even showed a mutual jumper sub-transformation. An eight-fold (!) Jumper sub-transformation can be found in André Chéron .
A sub-metamorphosis can also occur in the early stages of the game as an opening trap (for a well-known variant see Albin's counter-gambit ).
history
In the second half of the 19th century it was permissible to leave a pawn on the opponent's back row without converting it (until the end of the game if he was not captured beforehand). The English name for such a peasant was dummy pawn . The contemporary German name, if there was one, is lost; Tim Krabbé uses the translation Dummy-Bauer . It was enshrined in the laws of the British Chess Federation in 1862 and some of the first tournaments were played according to these rules, most recently in Vienna in 1873. A dummy pawn is hardly ever necessary in practical games. However, there are some chess compositions with this theme. In 1903 this option was abolished again.
A dummy farmer could be particularly useful for forcing a self-puncture, as the following illustration shows:
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After 1. b7 – b8B White is paused in any case, whereas any other move leads to a loss if Black plays sensibly.
The American puzzle expert Samuel Loyd composed a three-move in which a white pawn must hit a black rook on the back row and then remain pawn, as every converted piece allows black stalemates.
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After the key move 1. c7xd8B! (threatens 2. f7 – f8D) the following variants result:
1.… Bd7 – f5 + 2. Re5xf5 Kd6 – e7 3. f7 – f8D #
1.… Bd7 – c6 + 2. b5xc6 Kd6xc6 3. b4 – b5 #
1.… Bd7xc8 2. f7 – f8D + Kd6 – d7 3. Qf8 – e7 #
Not
achieving the goal: 1. c7xd8L? Bd7 – f5 + 2. Ke4 – d4 Bf5xc8
1. c7xd8S? Bd7-c6 + 2nd Ke4-d4 Bc6xa8
In 1972 and 1974, respectively, it was discovered that the literal formulation of the castling rule made it possible to castle on the king's line instead of on the back row after being transformed into a rook . This so-called Pam Krabbé castling was published in the form of a joke task. Then the formulation of the castling rule was made more precise.
frequency
Berlin 1863
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Sub-metamorphoses are extremely rare in games. The Dutch chess curiosity collector Tim Krabbé has compiled a few dozen sub-transformations in games since 1863 on his website. He only considered actually meaningful sub-transformations, i.e. no joking sub-transformations if the stone has to be struck anyway or a winning position has been reached anyway. In some of the positions, sub-transformation is the easiest way and in others it is even necessary. In the diagram position, for example, Black, seeing the only way to win, won with 1.… a3 – a2 + 2. Kb1 – b2 b3xc2 3. Kb2xa2 c2 – c1T! and white gave up.
Knight conversions are more common, with the game between László Szabó and Borislav Ivkov in Belgrade 1964 being a specialty: After Ivkov's conversion on move 49, there were five knights on the board. Ivkov won.
At the 2012 Chess Olympiad (game example, see there), Hikaru Nakamura (United States) achieved the final victory against ex-world champion Vladimir Kramnik (Russia) by converting a knight . This cost Russia a team point; In the end, Armenia won, level with Russia, thanks to the better ranking .
See also
literature
- Yochanan Afek : When less is more. The art of sub-transformation. In: Karl 3/2018, pp. 46–53.
Web links
- FIDE Handbook of Chess Rules - German translation
- Tim Krabbé: Practical underpromotion (English)
- Szabó-Ivkov - Belgrade 1964 game with 5 jumpers - at chessgames.com