The Chess Variant Pages




Rococo

by

Peter Aronson and David Howe

Introduction

          In his article, What's Wrong with Ultima (originally published in Michael Keller's WGR), Robert Abbott complains that his game Ultima favors the defense over the attack, and is lacking in clarity. Rococo started life as a revision of Ultima designed to cure these problems. The result, however, is rather far from Ultima, but still seems to be an interesting game in its own right, where attack is stronger than defense, and that possesses reasonable clarity.

Rules

          The rules of Rococo are identical to those of International Chess, except when noted below. The largest general rules change is that the object of the game is to capture the opposing King, not to checkmate it. Also, a player unable to move or who causes three time repetition loses as well.

          The 36 outer squares of the 10 x 10 Rococo board are marked in the diagram below. These marked squares on the edge of the board are edge squares, and a move may only pass over or end on an edge square if it is necessary for a capture. (Or in other words, a piece may only end up on an edge square by making a capturing move that would not be possible without landing on the edge square.) This includes moves that start on edge squares. Also, only the minimal number of edge squares may be passed over in order for the capture to occur, thus:

A Long Leaper on x00 could capture an opposing piece on x3 by landing on x2 (assuming x8-x4 were empty), but may not capture an opposing piece on x3 by landing on x1 or x0.
(This is a clarification of the original rules which failed unambiguously to define the appropriate behavior in this case.) Moves that captures of multiple opposing pieces are not forbidden by edge squares -- the piece may move over as many edge squares as required for the capture. While a capture must be performed crossing as few as possible edge squares, when there is a choice among multiple possible captures, there is no requirement to choose the capture that crosses the fewest possible edge squares. The Swapper's swap move is considered a capture for purposes of edge squares.

          To describe the rules for edge squares formally:

  1. A move to an edge square (e) must involve a capturing move (c).
  2. A capturing move (c) is distinguished by a capturing piece p on square s making a move that captures a set of one or more pieces P (p1, p2, ..., pN) on a set of particular squares S (s1, s2, s3, ..., sN).
  3. A move to the particular edge square e must be the shortest move that would accomplish the particular capturing move c.
  4. A move to the particular edge square e must be the only legal move (as restricted by the previous rule) that would accomplish the particular capturing move c.

Board and Setup

          Each player starts with 8 Cannon Pawns, 1 Advancer, 1 Chameleon, 1 Immobilizer, 2 Long Leapers, 1 Swapper, 1 Withdrawer and 1 King. The board is like the ring board from Jumping Chess, whose outer ring is special in that it can only be entered when required to to make a capture.
Rococo Board.
              +---+---+---+---+---+---+---+---+---+---+
          00  | * | * | * | * | * | * | * | * | * | * |
              +---+---+---+---+---+---+---+---+---+---+
           8  | * | I |:W:| L |:K:| C |:L:| A |:S:| * |
              +---+---+---+---+---+---+---+---+---+---+
           7  | * |:P:| P |:P:| P |:P:| P |:P:| P | * |
              +---+---+---+---+---+---+---+---+---+---+
           6  | * |   |:::|   |:::|   |:::|   |:::| * |
              +---+---+---+---+---+---+---+---+---+---+
           5  | * |:::|   |:::|   |:::|   |:::|   | * |
              +---+---+---+---+---+---+---+---+---+---+
           4  | * |   |:::|   |:::|   |:::|   |:::| * |
              +---+---+---+---+---+---+---+---+---+---+
           3  | * |:::|   |:::|   |:::|   |:::|   | * |
              +---+---+---+---+---+---+---+---+---+---+
           2  | * | p |:p:| p |:p:| p |:p:| p |:p:| * |
              +---+---+---+---+---+---+---+---+---+---+
           1  | * |:i:| w |:l:| k |:c:| l |:a:| s | * |
              +---+---+---+---+---+---+---+---+---+---+
           0  | * | * | * | * | * | * | * | * | * | * |
              +---+---+---+---+---+---+---+---+---+---+
                x   a   b   c   d   e   f   g   h   y
White
King (K): e1
Advancer (A): g1
Chameleon (C): e1
Immobilizer (I): a1
Long Leapers (L): c1 f1
Swapper (S): h1
Withdrawer (W): b1
Pawns (P): a2 b2 c2 d2 e2 f2 g2 h2
Black
King (k): e8
Advancer (a): g8
Chameleon (c): e8
Immobilizer (i): a8
Long Leapers (l): c8 f8
Swapper (s): h8
Withdrawer (w): b8
Pawns (p): a7 b7 c7 d7 e7 f7 g7 h7

The Pieces and their Movements

          For those readers using graphic browsers, there is an animated illustration of each piece's move (other than the King's) available by clicking on the Animated Illustration link for each piece.
Piece Description
k
King
The King moves and captures as an Orthodox Chess King. Since victory is by capture of the opposing King, a Rococo King may move next to an enemy King. A King may only enter an edge square to capture a piece on an edge square.
a
Advancer
The Advancer moves passively as an Orthodox Queen. In order to capture, the Advancer must move to a square adjacent to an enemy piece. If the next square in the direction it moved from the square the Advancer stopped on is occupied by an opposing piece, that opposing piece is captured. (This is capture by approach.) These captures are part of movement, and are not optional -- you can not move a Advancer next to an opposing piece in the line of movement and not capture it. An Advancer never moves into an occupied square. An Advancer may only enter an edge square if swapped there, but once on an edge square it may make capturing moves along the edge.
+---+---+---+---+---+---+---+
|:::| p |:::|   |:::|   |:::|
+---+---+---+---+---+---+---+
|   |:*:|   |:::|   |:p:|   |
+---+---+---+---+---+---+---+
|:::| + |:::|   |:*:|   |:::|
+---+---+---+---+---+---+---+
|   |:+:|   |:+:|   |:::|   |
+---+---+---+---+---+---+---+
|:+:| + |:+:|   |:::|   |:::|
+---+---+---+---+---+---+---+
| + |:A:| + |:+:| * |:p:|   |
+---+---+---+---+---+---+---+
|:+:| + |:+:|   |:::|   |:::|
+---+---+---+---+---+---+---+
The '+'s indicate where the white Advancer can move without capturing, and the '*'s indicates where it may move to to capture one of the black Pawns.

Animated Illustration.

l
Long Leaper
The Long Leaper moves as an Orthodox Queen and captures by overtaking. It takes possession of a single intervening piece by leaping to a vacant square somewhere beyond it. It may capture additional pieces, along the same line, if a vacant 'landing square' lies somewhere beyond each enemy piece. A Long Leaper may never jump over a friendly piece, jump over two or more pieces in a row without any empty spaces between, or move to an occupied square. It may end its move on an edge square only when that is the only way to make a particular capture.
+---+---+---+---+---+---+---+---+
|:*:|   |:::|   |:::|   |:::| * |
+---+---+---+---+---+---+---+---+
| * |:::|   |:::|   |:::| * |:::|
+---+---+---+---+---+---+---+---+
|:*:|   |:::|   |:::| p |:::|   |
+---+---+---+---+---+---+---+---+
| * |:::|   |:::| + |:::|   |:::|
+---+---+---+---+---+---+---+---+
|:*:|   |:::| + |:::|   |:::|   |
+---+---+---+---+---+---+---+---+
| p |:::| + |:::|   |:::|   |:::|
+---+---+---+---+---+---+---+---+
|:+:| + |:::|   |:::|   |:::|   |
+---+---+---+---+---+---+---+---+
| L |:+:| + |:+:| + |:+:| p |:*:|
+---+---+---+---+---+---+---+---+
The '*'s indicate squares the could be landed in after leaping over and capturing an opposing piece, the '+'s indicate squares that can be moved to without capturing.

Animated Illustration.

s
Swapper
The Swapper moves as an Orthodox Queen without capturing, or may swap position with any piece (of either side) an unobstructed Queen's move away. A Swapper's swap move counts as a capture for the purpose of the edge squares, so a Swapper may swap position with a piece on an edge square. Additionally, a Swapper may capture an adjacent piece and itself at the same time by mutual destruction. Mutual destruction may not be used when immobilized. If a Swapper swaps with an opposing Swapper or Chameleon, on the following turn the two pieces may not swap back. They may swap again once any other move is made.

The Swapper (without the capture by mutual destruction) was called the Ximaera and the Chimaerine by V.R. Parton.

Animated Illustration.

w
Withdrawer
The Withdrawer moves passively as an Orthodox Queen. In order to capture, the Withdrawer must occupy a square adjacent to an enemy piece. To complete the capture, it must move one-or-more squares directly away from the enemy piece. For example, a Withdrawer moving from d2 to g2 captures only an enemy piece at c2 (not c3/d3/e3/c1/d1/e1). These captures are part of movement, and are not optional -- you can not move a Withdrawer directly away from an opposing piece and not capture it. A Withdrawer may never move to an occupied square. It may move to an edge square when it is the only way to make a particular capture.
+---+---+---+---+---+---+---+---+
|:::|   |:::| * |:::|   |:::| + |
+---+---+---+---+---+---+---+---+
|   |:::|   |:*:|   |:::| + |:::|
+---+---+---+---+---+---+---+---+
|:::|   |:::| * |:::| + |:::|   |
+---+---+---+---+---+---+---+---+
|   |:::| p |:*:| + |:::|   |:::|
+---+---+---+---+---+---+---+---+
|:+:| + |:+:| W |:+:| + |:+:| + |
+---+---+---+---+---+---+---+---+
|   |:::| + |:p:| * |:::|   |:::|
+---+---+---+---+---+---+---+---+
|:::| + |:::|   |:::| * |:::|   |
+---+---+---+---+---+---+---+---+
| + |:::|   |:::|   |:::| * |:::|
+---+---+---+---+---+---+---+---+
The '*'s indicate squares the could be landed in after moving away from and capturing an opposing piece, the '+'s indicate squares that can be moved to without capturing.

Animated Illustration.

i
Immobilizer
The Immobilizer moves as an Orthodox Queen but does not capture. An enemy piece standing adjacent to an Immobilizer may not move while the Immobilizer is present. Black and white Immobilizers, occupying adjacent squares, are each frozen until the other is captured. An immobilized piece other than a King may 'commit suicide' by removing itself from the board (usually to open a line of attack). This counts as a move for the player removing the piece. The Immobilizer may never move to an occupied square or an edge square (although it may be swapped to an edge square).

Animated Illustration.

i
Chameleon
The Chameleon moves passively as an Orthodox Queen. To capture, it mimics the powers of its intended victim. For example, it leaps over a mount to capture a Pawn, withdraws from Withdrawers, approaches Advancers, leaps over Long Leapers, and swaps with Swappers. By the same token, an enemy King standing adjacent to a Chameleon can be captured by the Chameleon. Chameleons can freeze Immobilizers but cannot capture them (but when next to an Immobilizer do not freeze any other pieces). A Chameleon next to a Swapper may capture it (and itself) by mutual destruction.

A Chameleon can use multiple types of capture in the same move. Consider a white Withdrawer on a1, a black Chameleon on a2, a white Long Leaper on a3 and a white Advancer on a5. The Black Chameleon by leaping over the Long Leaper to a4 would also capture the white Withdrawer by moving away from it, and the white Advancer by approaching it (for purposes of approaching and withdrawing it doesn't matter if the move is a slide or a leap). Swaps with Swappers may be combined with other captures.

Animated Illustration.

p
Cannon Pawn
The Pawns in Rococo are Cannon Pawns, since their move is rather like a limited form of the Cannon from XiangQi (although, their move is even more like the fairy Chess piece called the Grasshopper). Cannon Pawns move without capturing two ways: either a single step in any direction, or, they may leap over an adjacent piece of either side to the empty square just beyond. They capture the in the second way they move, by leaping over an adjacent piece (the mount), landing on the opposing piece just beyond the mount. A Cannon Pawn may only move to an edge square when capturing a piece on an edge square.
+---+---+---+---+---+---+---+---+
|:::|   |:::|   |:::|   |:::|   |
+---+---+---+---+---+---+---+---+
|   |:::|   |:::|   |:::|   |:::|
+---+---+---+---+---+---+---+---+
|:::|   |:::|   |:::|   |:::|   |
+---+---+---+---+---+---+---+---+
|   |:::|   |[p]|   |:*:|   |:::|
+---+---+---+---+---+---+---+---+
|:::|   |:+:| A |:p:|   |:::|   |
+---+---+---+---+---+---+---+---+
|   |:::| + |:P:| + |:::|   |:::|
+---+---+---+---+---+---+---+---+
|:::|   |:+:| + |:+:|   |:::|   |
+---+---+---+---+---+---+---+---+
|   |:::|   |:::|   |:::|   |:::|
+---+---+---+---+---+---+---+---+
The '*'s indicate squares the could be landed on by leaping over another piece. The '+'s indicate squares that can be moved to without jumping. The Pawn surrounded by '[]'s can be captured by leaping over the Advancer (the mount in that case).

If a Cannon Pawn makes a move by itself (rather than being swapped) that lands it on a square on the rank where the opposing King started, or on the edge rank past it, it may promote to any friendly piece other than a Cannon Pawn that has been captured and is currently off of the board.

Animated Illustration.

Notes and Comments

          Most of the differences between Rococo and Ultima were the result of "fixing" the problems that Robert Abbott had pointed out with Ultima in one place or another:

  • The edge squares were to avoid pieces being able to hide from Long Leapers around the edges. (The idea of adding edge squares that can only be entered in order to capture was borrowed from Jumping Chess.)
  • The Cannon Pawns were a way to avoid the lack of clarity, edge weakness, and defensive advantage of Pincer Pawns (experience in general has shown that capture by interception favors the defense -- this is a problem with many attempts to recreate ancient Roman and Greek strategy games).
  • The Swapper replaced the Coordinator, again to increase clarity.
  • The Advancer was a high clarity piece added to replace some of the attack power lost by removing the Coordinator.

The other changes, such as the change in the array, victory by capture and Pawn promotion were the results of play-testing and experimentation.

          In Ultima, no two pieces use the same form of capture. Purists might complain that Rococo breaks that rule, since both the King and the Cannon Pawns capture by replacement. Our view is that doesn't make it the same type of capture, since by that reasoning, capture by approach, withdrawal and overtaking are all forms of capture by relative movement. Direct replacement and leaping replacement are at least as different as those three forms of capture are from each other.

          Is Rococo the "fixed" version of Ultima? Probably not. Instead, Rococo is a game in the Ultima family, with its own strengths and weaknesses. It is a very aggressive game, reminiscent of XiangQi in that position is often more important than material. It seems to be a game with a fair degree of clarity too.

Equipment

          Rococo can barely be played with a regular Western Chess set if there is enough of a border to the board so that pieces on edge squares can be placed just past the end of the grid. Rooks and Bishops will have to be distinguished, with one Rook being the Immobilizer and the other the Swapper, and one Bishop being the Withdrawer and one being the Advancer, and the Knights are the Long Leapers and the Queen is the Chameleon. It is certainly easier to play with an actual 10x10 board.

Variants

Rococo with Pushme-Pullyus

          In developing his as yet unpublished game Supremo (a related project to Rococo), Fergus Duniho invented a piece that combined the capturing powers of an Advancer and a Withdrawer, which he called the Pushme-Pullyu, after a creature in Docter Dolittle. In this variant of Rococo, the Pushme-Pullyu replaces both the Advancer and the Withdrawer in the opening array.
Piece Description
u
Pushme-Pullyu
The Pushme-Pullyu moves like a Queen, but never to an occupied square. If it moves directly away from an adjacent opposing piece, it will capture it like a Withdrawer. If it moves directly next to an opposing piece in its direction of movement, it will capture it like an Advancer. It may combine both types of capture in a single move. These captures are part of movement, and are not optional -- you can not move a Pushme-Pullyu directly away from an opposing piece and not capture it. Pushme-Pullyu's can enter edge squares when required to in order to capture by withdrawal. When on an edge square it may move to another edge square in order to capture by approach or withdrawal.

Rococo with Mirror Arrays

          Rococo is normally played with matching arrays for both sides, but it can be played with mirror arrays like Ultima. Black's back row is simply ordered: Swapper, Long Leaper, Advancer, Chameleon, King, Withdrawer, Long Leaper, Immobilizer, while White's back row is ordered in the usual way. This particular variant has gotten some club play in Venezuela.

Rococo with Enhanced Withdrawers

          In this variant, the Withdrawer -- the weakest of the backrow pieces -- is enhanced by making it immune to the effect of the Immobilizer. This still leaves it a fairly weak piece, but gives it an additional role in hounding the powerful Immobilizer. It does, however, make the piece asymmetrical in behavior with the its "partner" the Advancer.

Computer Play

          An implementation of Rococo has been written for Zillions of Games. You can download it here:


Written by Peter Aronson, graphics by David Howe.
WWW page created: May 19th, 2002.
WWW page modified: April 10th, 2005.