GROSSRAUMSCHACH

As the name suggests, this is an enlarged form of Raumschach, gross being the German for great or grand. There are four elements to the enlargement.
(1) All dimensions are increased from 5 cells to 6 giving a total of 216, a gross and a half. A bare gross, 6x6x4, might have done had I not decided that
(2) the number of armies is doubled to four playing in the order Red, Orange, Green, Blue. When using physical pieces it may be best to attach coloured string or plasticene rather than paint them, as the colours will prove far from permanent. To fill out the enlarged dimensions
(3) the Unicorns per army are increased to 4, so that an army's Unicorns cover the board and
(4) the Pawns are increased to 12 to remain half the army.

There are two minor alterations that do not affect the game materially but are best explained next. Firstly as with my original 3d game, Tunnelchess, I reserve FIDE names for pieces with no nostandard diagonal (commonly called triagonal) move, so the pieces termed King and Queen in standard Raumschach are termed Emperor (E) and Empress (S) in this game. A case could even be made for extending this usage to standard Raumschach, which was invented in a Germany that had an Emperor at the time! Secondly the whole thing is turned on its side for symmetry's sake. This way each player has their own corner, with the armies arranged anticlockwise in turn order.

As with my first 4-player game, Fivequarters, there are leftranks and rightranks, but notational order matters as there are also levels. Each cell has a leftrank number, followed by a level letter, and then a rightrank number (e.g. 1a1). An intersection of leftrank and level is a rightfile (e.g. 1a), an intersection of rightrank and level is a leftfile (e.g. a1), and an intersection of leftrank and rightrank is a rankling. Initially the pieces RUSEUR occupy each corner rankling, from level A (top) to level F (bottom) - Red on 16, Orange on 66, Green on 61, and Blue on 11. The pieces NUBBUN occupy ranklings 15, 56, 62, and 21. Ranklings 25, 26, 55, 65, 52, 51, 22, and 12 are filled with Pawns. This arrangement restores one FIDE feature missing in standard Raumschach: the strongest piece cannot make the first move.

As this is a 3d variant, with total army strength at a premium, captured pieces may be reintroduced Shogi-style as pieces of the capturer, but WITHOUT demotion back to Pawn. When a player is checkmated their capturable pieces remain in place but immovable, and may be captured and reintroduced in the same manner. Finalist armies may well differ greatly in size, but the stronger might still need all that strength to checkmate the weaker!

The larger size compared to standard Raumschach allows a simpler Pawn move. Pawns move one cell orthogonally anticlockwise, toward the next player's camp. When capturing they move on any diagonal with a component in that direction. Conversely more adventurous players may wish to try an alternative variant substituting an alternartive from my piece article Shield Bearers. I can particularly recommend WARDERS, which make the Pawn's capturing moves when NOT capturing, and move on the corresponsding NONstandard diagonal when capturing. With promotion after four moves, the trek is too short for an initial double move with either piece.

Although this is both a 3d AND 4-player variant of mine, castling is possible as each player's King and Rooks are on a common oerthogonal, vix the corner ranklings. To castle the King moves to level B and the level-A Rook to level C, remaining on the same rankling. Both must be previously unmoved and the destination cells empty. The King must not castle into, out of, or through check.

You may wish to mark cells for Unicorn bindings as well as Bishop ones. If so, colours are determined by the royal couples: 1c1 is dark blue, 1d1 pale yellow, 1c6 pale red, 1d6 dark green, 6c6 dark yellow, 6d6 pale blue, 6c1 pale green, and 6d1 dark red. Shades represent the two domains of the Bishops, and what they are shades OF represent the four of the Unicorns. Thus orthogonal moves alternate between opposite shades of two colours, diagonal moves between the same shade of two colours, and triagonal moves between opposite shades of one colour.

I have since added a family of two-player variants on a similar board: Unionschach, Sachsenschach, and Leapale.