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Topic: Answer about Chess960??? (Resposta sobre Chess960???)
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It's fun, interesting and challenging. No more Sicilians nor Ruy Lopezes. It is thus a great equalizer. Try it, somewhere.
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What on earth are you talking about...
And why is this in the 'Help and Support' section?
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I should have put in Chess Discussion  .
Ps:But it helps.
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Rules
Before the game a starting position is randomly set up, subject to certain rules. After this, the game is played in the same way as standard chess. In particular, pieces and pawns have their normal moves, and each player's objective is to checkmate the opponent's king.
Starting position requirements
The starting position for Fischer Random Chess must meet certain rules. White pawns are placed on the second rank as in regular chess. All remaining white pieces are placed randomly on the first rank, but with the following restrictions:
* The king is placed somewhere between the rooks.
* The bishops are placed on opposite-colored squares.
The black pieces are placed equal-and-opposite to the white pieces. For example, if the white king is placed on f1, then the black king is placed on f8. Note that the king never starts on file a or h, because there would be no room for a rook. The starting position can be generated before the game either by a computer program, players choosing a starting position by a variety of methods, or using dice, coin, cards, etc.
Determining a starting position
There are many procedures for creating this starting position. A common one is that proposed by Hans L. Bodlaender, which uses one six-sided die to create an initial position. Typically this is done just before the game commences:
* Roll the die, and place a white bishop on the black square indicated by the die, counting from the left. Thus 1 indicates the first black square from the left (a1 in algebraic notation), 2 indicates the second black square from the left (c1), 3 indicates the third (e1), and 4 indicates the fourth (g1). Since there are no fifth or sixth positions, re-roll 5 or 6 until another number shows.
* Roll the die, and place a white bishop on the white square indicated (1 indicates b1, 2 indicates d1, and so on). Re-roll 5 or 6.
* Roll the die, and place the queen on the first empty position indicated (always skipping filled positions). Thus, a 1 places the queen on the first (leftmost) empty position, while a 6 places the queen on the sixth (rightmost) empty position.
* Roll the die, and place a knight on the empty position indicated. Re-roll a 6.
* Roll the die, and place a knight on the empty position indicated. Re-roll a 5 or 6.
* This leaves three empty squares. Place the king on the middle empty square, and the rooks on the remaining two squares.
* Place all white and black pawns on their usual squares, and place Black's pieces to exactly mirror White's (so Black should have on a8 exactly the same type of piece that White has on a1, except that bishops would be on opposite colors).
This procedure generates any of the 960 possible initial positions with an equal chance. This particular procedure uses an average 6.7 die rolls. Note that one of these initial positions (rolled by 2-3-3-2-3 or 2-3-3-4-2) is the standard chess position, at which point a standard chess game begins.
It is also possible to use this procedure to see why there are exactly 960 possible initial positions. Each bishop can take one of four positions, the queen one of six, and the two knights can have five or four possible positions, respectively. (That leaves three open squares and the king must occupy the middle of those three squares, with rooks taking the last two squares, with no choice.) This means that there are 4×4×6×5×4 = 1920 possible positions if the two knights were different in some way. However, the two knights are indistinguishable during play; if they were swapped, there would be no difference. This means that the number of distinguishable positions is half of 1920, or 1920/2 = 960 possible distinguishable positions. Although half of these remaining positions are visual mirror-images of the other half, the rules for castling (below) preserve some left-right asymmetry in play.
Rules for castling
Fischer Random Chess allows each player to castle once per game, moving both the king and a rook in a single move. However, a few reinterpretations of standard chess rules are needed for castling, because the standard rules presume initial locations of the rook and king that often do not apply in Fischer Random Chess games.
After castling, the rook and king's final positions are exactly the same as they would be in standard chess. Thus, after a-side castling (also called sometimes c-castling) the king is on c-file (c1 for White and c8 for Black) and the a-side Rook is on d-file (d1 for White and d8 for Black). This castling notated as O-O-O and known as queenside castling in orthodox chess. After h-side castling (also called sometimes g-castling) the King is on g-file and the h-side Rook is on f-file. This move notated as O-O and known as kingside castling in orthodox chess. It is recommended that a player state "I am about to castle" before castling, to eliminate potential misunderstanding.
However, castling may only occur under the following conditions. The first two are identical to the standard chess castling rules. The third is an extension of the standard chess rule, which requires only that the squares between the king and castling rook must be vacant.
1. Unmoved: The king and the castling rook must not have moved before in the game, including castling.
2. Unattacked: No square between the king's initial and final squares (including the initial and final squares) may be under attack by any opposing piece.
3. Unimpeded: All the squares between the king's initial and final squares (including the final square), and all of the squares between the rook's initial and final squares (including the final square), must be vacant except for the king and castling rook. An equivalent way of stating this is that the smallest back rank interval containing the king, the castling rook, and their destination squares contains no pieces other than the king and castling rook.
If the initial position happens to be the standard chess initial position, these castling rules have exactly the same effect as the standard chess castling rules. In some starting positions, some squares can stay filled during castling that would have to be vacant in standard chess. For example, after a-side castling (O-O-O), it's possible to have a, b, and/or e still filled, and after h-side castling (O-O), it's possible to have e and/or h filled. In some starting positions, the king or rook (but not both) do not move during castling.
How to castle
When castling on a physical board with a human player, it is recommended that the king be moved outside the playing surface next to his final position, the rook then be moved from its starting to ending position, and then the king be placed on his final square. This is always unambiguous, and is a simple rule to follow.
Eric van Reem suggests other ways to castle:
* If only the rook needs to move (jumping over the king), you can simply move only the rook.
* If only the king needs to move (jumping over the castling rook), you can simply move the king.
* One can pick up both the king and rook (in either order), then place them on their final squares (this is called "transposition" castling).
* One can move the king to its final square and move the rook to its final square as two separate moves in either order (this is called "double-move" castling). Obviously, if the rook is on the square the king will occupy, the player needs to move the rook first, and if the king is on the square the rook will occupy, the player needs to move the king first.
In the meantime there has been an adjustment setting of the WNCA that when performing a castling move it is irrelevant in which sequence involved pieces were touched. All pieces involved in a move may be touched arbitrarily. When castling those pieces are the King and Rook, and in capturing moves they are the capturing and the captured piece. Especially with players new to Fischer Random Chess it might make sense also to announce a castling to avoid misunderstandings. When a chess clock will be used, pressing the button could be taken as a sign that a castling move has been completed.
When castling using a computer interface, programs should have separate a-side (O-O-O) and h-side (O-O) castling actions (e.g., as a button or menu item). Ideally, programs should also be able to detect a king or rook move that cannot be anything other than a castling move and consider that a castling move. Recommended gestures are: the King is moving to his at least two steps distant castling target square or else upon the involved Rook, to avoid by this a possible confusion with normal King's moves.
When using an electronic board, to castle one should remove the king, remove the castling rook, place the castling rook on its new position, and then place the king on its new position. This will create an unambiguous move for electronic boards, which often only have sensors that can detect the presence or absence of an object on each square (and cannot tell what object is on the square). Ideally, electronic boards should detect a king or rook move that can only be a castling move as well, but users should not count on this.
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