Omega Chess

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Omega Chess starting position

Omega Chess is a commercial chess variant designed by Daniel MacDonald. The game is played on a 10×10 board with four extra squares, one added diagonally adjacent to the corner squares.[1] The game is laid out like standard chess with the addition of a champion in each corner of the 10×10 board and a wizard in each new added square.

Part of the reason for adding the new pieces was to equalize the number of jumping pieces with sliding pieces. The wizard was created specially to be a color-bound piece, an analog to the bishop. Because of the symmetry and four additional corners, Omega Chess creates new tactical possibilities, including the possibility of checkmate with two knights.

Omega Chess has garnered endorsements by grandmasters Michael Rohde[2] and Alex Sherzer.


Differences from standard chess

New pieces

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The champion can leap to any of the black crosses. The wizard can leap to any of the black dots or capture the knight.
  • Champions: are, like knights, classed as leapers. A champion can jump two squares orthogonally or diagonally, or slide one square orthogonally. White's king champion can start the game by Ch2 or Cj2. In the position shown at the right, the black champion's movement is indicated by an X, and it cannot capture the white knight. The champion is represented as WAD in Betza notation, combining the moves of the wazir, alfil, and dabbaba.
  • Wizards: are also classed as leapers, but, like a bishop, is a color-bound piece and jumps (1,3) or (3,1) squares in any direction, or slides one square diagonally. White's king wizard can start the game by Wj2. In the position shown at the right, the black wizard's movement is indicated by a black dot, and it can capture the white knight. The wizard is represented as FL in Betza notation, combining the moves of the ferz and camel.

Pawns

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Pawn's first move, en passant and castling
  • The pawn can advance one, two or three squares forward, on its first move only. This is shown on the a-, b- and d-files, respectively.
  • Capture, promotion and movement (following the first move) are otherwise identical to the pawn in standard chess.
  • The en passant rule also applies. A pawn that moves three squares may be captured en passant on either square, Thus, if d-pawn had just moved, it might be captured en passant by either black pawn. The b-pawn may be captured normally by the pawn on c4, and (if it had just moved) en passant by the pawn on c3.

Castling

The normal rules of castling apply. Also, it is done exactly as in chess, with the king moving two squares to either side: to h0 for White or h9 for Black when castling kingside; to d0 or d9 when castling queenside (see diagram).

Example games

As seen in the diagrams, the ranks are numbered 0–9, and the corner squares behind a0, j0, j9 and a9 are notated w1, w2, w3 and w4 respectively. It should be noted that these squares are part of the board, and all pieces (except rooks and pawns) can enter them. (See the puzzle by Benjamin Good.)

GM Alex Sherzer vs. GM Judit Polgár

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Position after 42.j4

1. f4 d5 2. Nd2 Ng7 3. Wa2 Cc7 4. Ng2 f7 5. Wj2 Wa7 6. e4 de4 7. Ne4 Bb4+ 8. Be1 Nd7 9. c3 Be7 10. Wi5 0-0 11. d4 Cc6 12. Bd3 b5 13. b4 Wd6 14. Cc2 Wj7 15. Ch2 Wi4 16. Nh4 Wh5 17. Wd1 We3+ 18. Kg0 c7 19. i4 Wg4 20. Be2 Wd5 21. Rc0 Bb7 22. Nc5 (Black is aiming a lot of artillery at the white king. Perhaps White should follow suit and play this knight to g5 instead of c5.) 22... Nc5 23. bc5 Qd8 24. Qh3 Wh4 25. Bh4 (Either on this move or the next, recapturing with the champion looks more promising.) 25... Bh4 26. Wh4 Ch7 27. Wg2 Ce4 28. Ce4 We4 29. Qj3 j7 30. i5 i6 31. Wg7 hg7 32. Ri3 Ki8 33. Qj4 Rh9 34. Rj3 Ci7 35. Re0 Qf6 36. Bc0 e6 37. Bb1 Wf5 38. Wf5 ef5 39. Re8 Rh8 40. Rje3 g6 41. Qi3 Qg7 42. j4 (see diagram) 42... b4! (Black seizes the initiative.) 43. R8e5 bc3 44. Rc3 Bh1 45. Kh1 Rb1 46. Ra3 Ch7 47. Ra8 Ch5 48. Ra9 Qh7 49. Ree9?? Cj3! 50. Qj3 Qh2+ 0–1[3]

Scholar's mate

1. f4 f5 2. Bc4 Bc5 3. Qj5 Ng7?? (defending the pawn on f5) 4. Qxg8#

Fool's mate

1. Wa2 Ni7 2. Wb5 Ng8?? 3. We6#

Endgames

The four corner squares in Omega Chess offer many endgame possibilities and peculiarities. For example, if you have two rooks, a bishop and a wizard against a lone king, you cannot win if the bishop and wizard attack one color, with the enemy king being on a corner square of the other color. This leads to the inevitable question of what combinations of reduced material can deliver mate.

Unlike in standard chess, a lone queen (without the king's assistance) can force mate. As well, two rooks find it easy to mate provided the enemy king is not in a wizard or champion starting square.

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King and rook vs. king

In the position diagrammed, White is obliged to check the enemy king back to the edge of the board, since Black isn't going to go there voluntarily. 1. Rd8+ Ke9 2. Ke7 Kf9 3. Kf7 (The white king must pursue the enemy king because when Black gets to i9, the white king wants to be on h7, controlling i8 so the rook can check on d9, forcing the king to j8, followed by Re8, Kj7, Rj8#) 3... Kg9 (Not 3...Ke8 because of 4.Rd6 Kf8 5.Rd8#) 4. Kg7 Kf9 (It is safe for the black king to double back. If the rook was on e8, then it could just retreat along the file and deliver mate next move. Or if it was on any other rank, it could now move to the e-file, but as it is the rook would be vulnerable to capture.)

Two bishops can deliver mate fairly easily, as can two knights, although in the latter case the task of herding the enemy king into a corner requires a lot of patience.[4]

Two champions mate easily and so do a champion and a knight. A bishop with a wizard on the opposite color squares can also force mate although technique is involved since the enemy king has to be driven into the same colored corner as the bishop.[5] However two wizards can't force mate. A rook in combination with either a knight or a champion can force mate easily and, provided the enemy king is not on the wrong colored wizard's square, (or corresponding champion's square) then both rook and bishop, and rook and wizard are also easy wins.

In the remaining combinations of material, bishop and champion, champion and wizard, bishop and knight, and knight and wizard, the requirement for winning is that the enemy king should be kept out of the wrong colored corner since the knight alone, or the champion alone cannot defeat the king. Having met this requirement, the mating technique for bishop and champion, and wizard and champion are fairly straightforward, while the technique for bishop and knight is somewhat more complicated.[6] As for knight and wizard, it is possible to set up positions in which the enemy king is corralled, leading to checkmate, but there doesn't seem to be a way of forcing these positions.

Omega Chess Advanced

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Omega Chess Advanced: The white fool immobilizes black queen, The black fool – white rook. Black dots show squares where the black fool may move to for freeing own queen from immobilizing. Crosses show knight moves; white dots show extra moves of white Templar Knight if unoccupied.

In 2008, the authors of Omega Chess developed an extension to the game called Omega Chess Advanced.[7]

  • A special move was introduced called Guarding. This move is equal to castling but it is executed by queen and rook. For Guarding to be legal, both the queen and rook must never have made any previous moves, and there may not be any pieces between them. Attacks are irrelevant. Notation is "S-S" or "S-S-S" for queenside or kingside.[8]
  • A new piece is introduced called the fool.[9] Each player starts with exactly one.
    • The fool has no starting position on the board. Instead, it can be "introduced" in the first 20 moves of the game, when its player's piece makes its first move, or makes a capture, by placing the Fool at that piece's vacated location. When castling or guarding, the fool can be placed on either of the two available squares.
      • Notation is "F". "*F" after a move indicates its "appearance", except when castling or guarding, where "F" replaces the relevant end-symbol (looking from White's side).
    • The fool threatens, moves and captures like the piece that the opponent last used. For example, if White moves a queen, then Black's fool is effectively a queen.
      • If the fool emulates a pawn, then only a single 1st move is allowed, and no promotion.
      • If a king, it cannot be checked, and cannot castle.
      • If a queen, it cannot be guarded.
      • If a fool, it copies the opponent's fool.
      • A pawn can be promoted to a fool.
      • A fool immediately copies a pawn's promotion (unless that is a fool, then it acts as a pawn).
      • A fool can jump from a wizard square to another empty wizard square.
    • "Check threat": after making one's move, an opponent's fool becomes the same piece for one move; if the fool would thus give immediate check, the move would have been illegal, thereby preventing the piece moving ("neutralizing" it) unless it moves to block the check or take the fool.
    • Reciprocal threat: Any piece moving to a position that attacks the opponent's fool is thus immediately threatened by the fool, and so could be taken; a "discovered" attack on the fool may prevent this ("indirect capture"), by moving a different type of piece out of the way instead.
    • If there are extra opponent's fools from promotions, much care is needed.
  • The following two rules are optional parts of Omega Chess Advanced:
    • The fool may immobilize an opponent's piece on an orthogonally adjacent square, thus preventing it from moving. In the figure to the right, the white fool has immobilized the black queen, and the black fool has immobilized the white rook. An immobilized piece can move again if the fool moves away or is captured. In addition, an immobilized piece can move if it is also orthogonally adjacent to a friendly fool.[10]
    • A new piece can replace the ordinary knight, called the Templar Knight. The Templar Knight moves like an ordinary knight, but it may choose to make a non-capturing (2,3)-leap rather than the usual (1,2)-leap. In the adjacent diagram, the white Templar Knight may move or capture to any of the squares marked with an X, or move to any of the squares marked with a white dot if they are unoccupied.[11]

Puzzle by Benjamin Good

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White mates in three

Solution: 1.Ww3+ :

  • 1...Kxw3 2.Bxh7#
  • 1...Ki9 2.Nj7+ Ki8 3.Bxh7#
  • 1...Ki8 2.Bxh7+ Ki9 3.Nj7#

References

  1. ↑ Dylan Loeb McClain (2007-08-19). "Giraffes, Viziers and Wizards: Variations on the Old Game". New York Times. Retrieved 2009-10-12.
  2. ↑ Grandmaster reviews.
  3. ↑ Omega Chess example game with the option to view the moves in a JavaScript viewer.
  4. ↑ Checkmate with two knights in Omega Chess, animated example.
  5. ↑ Checkmate with bishop and wizard in Omega Chess, animated example.
  6. ↑ Checkmate with knight and bishop in Omega Chess, animated example.
  7. ↑ Omega Chess Advanced official web site
  8. ↑ Definition of Guarding in Omega Chess Advanced
  9. ↑ Description of the fool piece
  10. ↑ Immobilization
  11. ↑ Templar Knight description
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