Taijitu Qi

The name reflects the Yin and Yang theme. As a European I judged that Yin Yang Qi sounded too like flying under false colours. Yin Yang on its own was too vague, and the title of another contributor's page began with it. Monad Qi might have been all right, the similarity to the word monarchy particularly suiting a variant with the full King, but suggested a nonexistent connection with Monadchess. I therefore put the words Yin, Yang, and Monad into a search engine and here is the most useful page that I found.

In combination with Inquisition Ashtaranga, this variant has also inspired Inquisitor Qi and Hoo Qi.

Setup

Pieces

	The KING moves one step in any of the 8 radial directions, and must be kept out of Check.
	The ROOK moves any distance orthogonally through empty squares. Rooks start where they always have, in the corners.
	The CANNON differs from the Rook in that capturing requires exactly one intervening piece, which may be of either army and is not itself captured. Cannons inherit their Xiang Qi array positions.
	The BISHOP moves any distance diagonally through empty squares. Bishops inherit their Yang Qi array positions.
	The ARROW differs from the Bishop in that capturing requires exactly one intervening piece, which may be of either army and is not itself captured. Arrows inherit their Yang Qi array positions.
	The KNIGHT makes any 2:1 leap, and in this variant cannot be blocked. Knights start where they always have, beside the Rooks.
	The WAZIR moves one step orthogonally. Wazirs start in the middle of the third rank.
	The FERZ moves one step diagonally. Displaced from their Xiang Qi positions by Arrows, Ferzes start at the opposite corners of the Fortress.
	The DABBABA moves exactly two cells in any of the 4 orthogonal directions. The version used in this variant is a stepping one, and the halfway square must be empty. Dabbabas start on a free location giving them a binding that includes the Elephant one.
	The ELEPHANT moves exactly two cells in any of the 4 diagonal directions. The version used in this variant is a stepping one, and the halfway square must be empty. Displaced from their Xiang Qi positions by Bishops, Elephants start one of their own moves away, to be on their traditional binding.

Rules

Promotion:
* A player moving a long-range piece into the enemy Fortress may, as a part of that move, promote a short-range piece of their own to a long-range piece captured by the enemy.
* If the moving piece is orthogonal, the short-range piece and its promotee must be diagonal, and vice versa.
* A player may not promote if it leaves their own Fortress empty of one-step pieces.
* A player may not have more than two pieces of any one type.

Other rules:
* There is no Castling.
* In place of a normal move, the King may swap places with any adjacent Yang Qi piece of the same army, including a Knight, if neither piece is threatened. This can help return it to the Fortress if required.
* Check, Checkmate, and Stalemate are as in FIDE Chess.

Notes