Quarter Chess

The board is 8x8, but consists of 4 different 4x4 quadrants. A double line shows where the quadrant ends.

Pieces move as they do in orthodox chess, but it's also possible to move to the corresponding square in another quadrant.

Setup

Starting position:
D	K	A	A	A	N	N	D
D	M	M	M	M	M	M	D
							
							
							
							
D	M	M	M	M	M	M	D
D	N	N	A	A	A	K	D

Starting position for black and white mirrors each other diametrically. Ranks 1, 2, 7 and 8 are occupied by pieces.

Pieces

A=Archbishop (knight + bishop compound).

D=Driver      The Driver moves exactly like a bishop does, but it can not take another piece the same way a bishop does. It can, like the bishop, never jump another piece. 

The driver can move any agent (friendly or not) that is closest to the driver along the files and ranks that a rook would have had access to. The moved agent can be moved one step closer to the driver along that rank or file. The moved agent does not have to be able to move accordingly, normally.  The driver can move black agents and white agents alike. The driver can also move other drivers. The driver remains on the square it occupied before the player made his move, and using the driver to move any agent counts as a move.

The driver is allowed to move a king in between two merchants of opposite color, and this counts as a win. For a single piece to be moved to a different square by a driver, it has to be at least two steps away. An enemy agent that is one step away, orthogonally speaking, can be absorbed by the driver, and the driver is unaffected by that action. If the absorbed agent was another driver, then the enemy driver will have been removed from the board, and the player's own driver remains on the same square as before. 

The driver can move any agent that is immobilized by a merchant. The driver can never itself be immobilized by a merchant. The driver can also absorb an immobilized enemy agent, or even absorb an enemy merchant. Drivers can be considered to outrank the merchants in those regards.

The driver can sometimes also move agents the other way, by pushing them. A prerequisite is that the agent about to be affected by the driver is right next square  in any of the four orthogonal directions. The push means the driver remains in place and that the pushed piece is moved one step away as the rook moves. The square that the pushed piece is about to end up in (before the theoretical push) must always be unoccupied right before the push. Both black and white pieces could be pushed by any driver.

The driver can also switch location of any two agents that are adjacent to
the driver, with both of them orthogonally adjacent, not diagonally. The driver must be in between the two for switching purposes.


M=Merchant    Merchants move one step in any of the four directions a rook could have moved in or one step in any of the four directions a bishop could have moved in. They don’t capture by displacement. Merchants can be taken out by enemy pieces that aren’t immobilized. 

Merchants immobilize most enemy agents (kings and most pieces) located
orthogonally adjacent to them. However, they don’t immobilize other
merchants or friendly agents, neither do they immobilize drivers. Any piece that is immobilized by a merchant can no longer give check or mate. 

It is allowed for an enemy agent (including the king) to move directly onto an immobilization square, either by taking a piece, pawn or merchant, or by just moving there.

Merchants take out enemy agents by custodian capture, but only when they step into an orthogonal configuration with the victim, and not when the victim steps in between them of own volition. Merchants do not perform custodian capture with the help of any other piece than another friendly merchant. Merchants will win the game if they are on opposite sides immediately next to the enemy King either horizontally or vertically. Merchants will win the game in such a position by “backstabbing” the enemy King. Giving check before custodian capture of the king is not necessary. Merchants can take out enemy merchants by custodian capture (even though they can’t immobilize them).

Agents that are next to both an enemy merchant and a friendly merchant
(orthogonally adjacent) will be able to move. That also goes if it is orthogonally adjacent to two enemy merchants but only one friendly merchant. Two merchants moving into backstabbing position next to an enemy agent will be able to backstab it even if the victim is next to a friendly merchant.

Rules

Change of rules from orthodox chess:
¤ The board is divided into 4 quadrants. All pieces, but not the kings, may move to any of the corresponding squares in the other 3 quadrants, but only as long as it’s an unoccupied square, and it doesn’t result in either check or mate. For instance, the square b2 corresponds to squares b6, f2, and f6 – since they’re located in corresponding places within the four quadrants. Drivers don’t give check,so they may shift quadrants unhindered by this rule. The 8x8 board works the same as in orthodox chess, so it’s entirely possible to move the ordinary way, crossing the border of the quadrant.
¤ Kings will only work as kings usually do, so there’s no change about the kings from how they work in orthodox chess. They can move to another quadrant the way it would have worked in orthodox chess, but they can't jump to the corresponding square in another quadrant.
¤ Drivers can not absorb the enemy king.
¤ There is no castling move.
¤ Mating the enemy king results in a win. If the enemy king is taken out by custodian capture (merchants), then it’s also a win.