Chaturanga with minor changes

Later I added two other basic variants. ETHELRED CHATURANGA, named after a king of pre-Norman England who was "unready", meaning unadvised, removed the Ferz - which was not among the four pieces that "chatu" means - and its file. Elephants remained on distinct bindings covering 8 squares each, but out of a total of only 56. TREBUCHETÉ CHATURANGA gave minor pieces an additional 3:0 leap, fully unbinding the inner ones but only marginally strengthened the Knight. Ethelred was incompatible with Batturanga, and Power with Trebucheté, but any other combination of two was valid.

Comments on my Kangaroo Piececlopedia entry, combined with the Carrera/Bird/Capablanca family of Bishop-era variants, inspired me to wonder about a variant with Ethelred pieces plus all their compounds (except King and Pawn ones). Having 10 files in the style of that family di d not suit this page, but using a standard board in the style of my Catholic Bishogi does. This arrangement I term CHATUKANGA as a pun on its inspiring piece. It includes by nature an Ethelred element (although without the reduced board), and I judge it incompatible with other modifications. I have since created a page for a 10x10 game with these pieces, Maha Chatukanga.

On reviewing this page with the intention to add Chatukanga I realised that my images for the Infanta and Trifle at the time, before I switched to a then recently introduced array designer, were the same. I wondered about giving one of the two a different image, but then I had a better idea. The Trebucheté modification was such an improvement over the unsatisfactory Power one that I may as well drop the latter, stripping the page of three pieces including the Trifle. This would also keep down the total number of variants on the page. So the Power variants have gone the way of Voyager and Heroic Round Chess - and others since.

Setup

Ethelred Chaturanga

Trebucheté Chaturanga

Chatukanga

Trebucheté Batturanga

Trebucheté Ethelred

Pieces

	PAWN: The familiar divergent front-rank piece. In Batturanga "Forward" is defined as the orthogonal most directly away from the King's starting square, and the six Pawns not on a long diagonal are promoted after four moves. The seventh Pawn can make a noncapturing move in either direction, and capture on any diagonal except toward its own King square. If it actually captures toward the enemy King square it retains that flexibility, but once it moves off the long diagonal it behaves like the three starting that side of it. To counter its initial strength it takes five moves from starting square to promotion.
	ROOK: The orthogonal linepiece, the same piece that has occupied corner squares across mainland Eurasia since Chaturanga as we know it was invented. In Batturanga its location has moved to the extremities of a right triangle of symmetric pieces rather than a straight row.
	KING: Moves one square orthogonally or diagonally, and must be kept out of check. In Batturanga the Kings oppose each other at opposite ends of a diagonal rather than a rank, the same diagonal that divides each player's Pawns.

	KNIGHT: The 2:1 leaper, again unchanged from Chaturanga at least in Occidental and Tropical variants. Knights cannot be blocked, and start orthogonally next to Rooks even in Batturanga.
	ELEPHANT or ALFIL: The 2:2 leaper, replaced with a stronger piece in most modern standard variants. Elephants cannot be blocked. In Ethelred all Elephants have different bindings, but each army's Elephants together cover one Dabbaba binding. In Batturanga each player's Elephants still cover 16 squares between them, but as in Byzantine Chess they are the same 16 for both armies so that Elephant can capture (but still not defend) Elephant. It is the reverse of Xiang Qi, whose Elephants (Stepping ones) can defend but not capture each other.
	FERZ: Moves one square diagonally, and is bound to half the board. In Batturanga, unlike Chaturanga but like some Byzantine arrays, Ferzes are bound to the same half of the board and one Ferz can capture the other. Unlike either historic variant both Elephant bindings are in the half of the board that the Ferz cannot reach, and so the Ferz can capture neither enemy Elephant and guard neither of its own - as against exactly one in the historic variants. This adds a symmetry to the relation between one Ferz and two Elephants. An interesting contrast is with Shatranj Kamil 64, which has the same defensive relations within an army but enables each colourbound piece to capture the other type instead of its own.

	CATAPULT: The combined 2:1 and 3:0 leaper, colourswitching like its components and so still unable to lose the move. Catapults cannot be blocked, and replace Knights in Trebucheté versions.
	NEWT: The combined 2:2 and 3:0 leaper. It is unbound and can lose the move in 7 moves, both powers unlike its components. Newts cannot be blocked, and replace Elephants in Trebucheté versions.
	FROG: The combined 1:1 and 3:0 leaper. It is unbound and can lose the move in 5 moves, both powers unlike its components. Frogs cannot be blocked, and replace Ferzes in Trebucheté versions.

Compounds of Ethelred pieces:

	INFANTA: The compound of Rook and Elephant. Blockable when moving as a Rook but not when moving as an Elephant. The name refers to the association between "Infanta de Castile" (a Spanish princess) and "Elephant and Castle" (an English pub name).
	MARSHAL: The compound of Rook and Knight. Blockable when moving as a Rook but not when moving as a Knight.
	KANGAROO: The compound of Knight and Elephant. Cannot be blocked. Named by Timothy Newton in Outback Chess.

Rules

Promotion in face-to-face variants is to the type of piece whose starting square the Pawn reaches except a King/Frog/Infanta square. There it becomes a Ferz in Ethelred, Frog in Trebucheté and Trebucheté Ethelred, or any array compound in Chatukanga. In Batturanga Pawns are not necessarily promoted on an enemy's starting square so Chaturanga rules are interpreted as follows: promotion is to Rook on a corner square, Knight on a square adjacent to a corner square, Elephant on one adjacent to that, and Ferz on one of an edge's middle two squares. Trebucheté Batturanga substitutes the corresponding compound pieces.

Bare King, Check, Checkmate, and Stalemate are as in Chaturanga.

Notes

Some people believe that the Rook replaced a Dabbaba that was the corner piece in a proto-Chaturanga. In a Trebucheté version of that game the corner piece would be the TOAD, the combined 2:0 and 3:0 leaper - making the full complement of amphibian square-board piece names known to me. The Toad is unbound and can lose the move in 5 moves, both powers unlike its components but like the Frog.

A further Elephant-unbinding modification, either to the original Chaturanga or to the original-piece variants is FUSION, from Fergus Duniho's Fusion Chess. The simplest form is Rex Pedesque Exclusive, in which Rook+Knight=Marshal, Rook+Ferz=CHATELAINE, Rook+Elephant=Infanta, Knight+Elephant=Kangaroo, Ferz+Knight=CARDILANDER, and Ferz+Elephant=FEARFUL. Another option is to take the King to be compound of a Ferz and the Xiang Qi GENERAL, and allow the latter to separate from the Ferz component and rejoin with a Rook, Knight, or Elephant to form a GENERRIDER, MARSHRULER, or WAFFLRULER respectively. Any piece with the General component would require keeping out of check.

Another way to increase Elephant coverage is QUINTELEPHANTINE CHESS, a pun on Jörg Knappen's Quintessential Chess and Terry Pratchett's The Fifth Elephant. Whenever there are four or fewer Elephants in total on the board, a player with an Elephant under threat can place an additional Elephant of their own army anywhere on the board. Doing so also has the advantages of: (1) raising total army size; (2) putting an Elephant in a strategically better position than the threatened one could reach; (3) forcing the enemy to capture an Elephant before they can add one of their own.