Omega Chess

Omega Chess is a commercial chess variant designed by Daniel MacDonald. The game is played on a 10×10 board with four extra squares, each added diagonally adjacent to the corner squares. 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 corner 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 and Alex Sherzer.
Differences from standard chess.
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 ; to d0 or d9 when castling (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. 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.
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 Nxc5 23. bxc5 Qd8 24. Qh3 Wxh4 25. Bxh4 Bxh4 26. Wxh4 Ch7 27. Wg2 Ce4 28. Cxe4 Wxe4 29. Qj3 j7 30. i5 i6 31. Wg7 hxg7 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 (diagram) b4 (Black seizes the initiative) 43. R8e5 bxc3 44. Rxc3 Bxh1+ 45. Kxh1 Rxb1 46. Ra3 Ch7 47. Rxa8 Ch5 48. Ra9 Qh7 49. Ree9 Cj3! 50. Qxj3 Qxh2+ 
Scholar's mate.
1. f4 f5 2. Bc4 Bc5 3. Qj5 Ng7?? (defending the pawn on f5) 4. Qxg8
Fool's mate.
1. Wa2 Ng7 2. Wb5 Ni6?? 3. We6#
Endgames.
The four corner squares in Omega Chess offer many endgame possibilities and peculiarities. For example, unlike in standard chess, a lone queen (without the king's assistance) can force mate. Two rooks find it easy to mate provided the enemy king is not in a wizard or champion starting square. However, a king and rook cannot force mate, as the rook alone cannot force the king to the edge without driving it into a corner where it is unassailable. Other material combinations leading to relatively straightforward forced wins include two bishops, two knights (also unlike standard chess; see two knights endgame), two champions, and champion and knight. The endgame with bishop and wizard (provided that they are on opposite colors) can also be won, though the technique is somewhat more complex. Other material combinations require that the king be kept out of the wrong-colored corner and thus a more precise technique; these include bishop and champion, wizard and champion, and bishop and knight.
Omega Chess Advanced.
In 2008, the authors of Omega Chess developed an extension to the game called "Omega Chess Advanced".