Community variant
Eco-friendly chess
If you take a tree you must place it down on an empty space where there was one.
Capture the enemy king or place 4 trees in a square to win !
This is a user-catalogued casual variant. Technical details such as board size,
FEN, pieces, and hand rules are defined in the Fairy-Stockfish
variants.ini block below.
Generated rule overview
This variant inherits its base rules from `chess` and overrides the settings shown below.
Board and setup
Pieces and movement
- The piece set used on the board is: commoner (k), queen (q), rook (r), bishop (b), knight (n), custom piece 1 (p), shogi pawn (t) and custom piece 2 (f).
- custom piece 1 (p) is a custom piece with Betza movement `mfWcfFifnD`.
- custom piece 2 (f) is a custom piece with Betza movement `K`.
- Some pieces have restricted movement regions: mobilityRegionWhiteShogiPawn is *4 *5.
- Some pieces have restricted movement regions: mobilityRegionBlackShogiPawn is *4 *5.
Move rules
- Dropping piece(s) t is mandatory when possible.
Drops and hands
- Pieces in hand can be dropped back onto the board. Droppable pieces are: commoner (k), queen (q), rook (r), bishop (b), knight (n), custom piece 1 (p), shogi pawn (t) and custom piece 2 (f).
- Captured pieces go to the capturer's hand.
- Piece drops are restricted to color-specific board regions. The the drop region for White is all the ranks from 4 to 5 and the drop region for Black is all the ranks from 4 to 5.
Promotion
- Promotions are available in the configured promotion zones. The the promotion region for White is all squares on rank 5 and the promotion region for Black is all squares on rank 4.
- The pieces that can promote are: custom piece 1 (p).
- Promotion choices are both sides: custom piece 2 (f).
Winning and losing
- An extinction rule is active: reaching 0 remaining piece(s) k causes a loss for the side to move.
- A player can win by forming a tight 2×2 block of pieces.
Piece movement
These diagrams show custom pieces and known Fairy-Stockfish built-in fairy pieces from White's perspective on a compact preview board. Some special moves, especially hoppers and game-state-dependent moves, can still depend on blockers or game state.
mfWcfFifnD
K
move
capture
move or capture
initial only
hopper target
Fairy-Stockfish rules
[eco-friendly:chess]
king = -
pawn = -
customPiece1 = p:mfWcfFifnD
commoner = k
castlingKingPiece = k
startFen = rnbqkbnr/pppppppp/8/TTTTTTTT/tttttttt/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
extinctionValue = loss
extinctionPieceTypes = k
shogiPawn = t
mobilityRegionWhiteShogiPawn = *4 *5
mobilityRegionBlackShogiPawn = *4 *5
pieceDrops = true
capturesToHand = true
mustDrop = true
mustDropType = t
dropRegionWhite = *4 *5
dropRegionBlack = *4 *5
pawnTypes = t
promotionRegionWhite = *5
promotionRegionBlack = *4
customPiece2 = f:K
promotionPieceTypes = f
connectNxN = 2
connectPieceTypes = t