p.boxed
  | Two new pieces: marshall and cardinal. Bigger board.
  | Orthodox rules with a few adaptations.

p.
  Grand chess is played on a 10x10 board.
  Two new pieces appear: the marshall and the cardinal, written respectively M and C.
  A marshall has the moving abilities of a knight + a rook, while the cardinal
  equals a knight + a bishop.

figure.diagram-container
  .diagram
    | fen:10/10/10/10/10/2R2Q4/10/4c5/10/10:
  figcaption The black cardinal can take on c5 and f5.

h3 Special moves

p.
  Castling is possible as in orthodox 8x8 game. The white king move to c1 or i1
  (one square to the left of bottom-right corner) for large (resp. small) castle.
  Same for black on the other side.

p.
  Promotion is mandatory for a pawn reaching the last rank. However, they can only
  promote into a friendly piece captured (which is back on the board). If none is
  available, the promotion on last rank is impossible and the pawn cannot move
  (but still gives check).

p.
  Pawn promotion is possible (but not forced) on the two ranks before last,
  only in an already captured (friendly) piece.

p.
  Note: I changed the author's starting position, to increase randomness
  (and uniformize with other variants).
  Thus the castling rule was introduced compared to the rules described
  on chessvariants.com.

h3 Source

p
  | Grand chess page on 
  a(href="https://www.chessvariants.com/large.dir/freeling.html") chessvariants.com
  | .

p Inventor: Christian Freeling (1984)