Omega Chess Advanced

**Omega Chess Advanced** is a collection of variants of Omega Chess origianally detailed in Omega Chess' home page. Players may follow any/some/all of the added rules to their liking.

## Summary

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

* 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.

* A new piece is introduced called the *fool*. 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.
	+ 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.