Community variant

tetrarchy

Created by @autocorr In this variant four pieces in the starting position are replaced with Tetrarchs. Tetrarchs flip between the move-set of a standard King or Queen when moved. All the rules of Chess apply except that: (1) there is no castling, (2) stalemate is a loss for the stalemated player, (3) a player wins if one of their Pawns reaches the final rank ("Pawn-mate"), and (4) a player loses if no Tetrarchs remain on the King side. Checks do not apply to the Tetrarchs.

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.

Uploaded by: gbtami
Visibility: public
Status: active

Generated rule overview

This variant is defined directly from a Fairy-Stockfish rule block. The text below is generated from the available configuration and may omit details that are only implicit in piece movement notation.

Board and setup

Default starting position

Pieces and movement

The piece set used on the board is: commoner (k), bishop (b), knight (n) and custom piece 1 (p).
custom piece 1 (p) is a custom piece with Betza movement `fmWfceFifmnD`.

Promotion

Promotions are available in the configured promotion zones. The the promotion region for White is all the ranks from 1 to 8 and the promotion region for Black is all the ranks from 8 to 1.
The pieces that can promote are: commoner (k).
Promotion choices are both sides: no pieces.
Fixed promotion mappings: k promotes to q.
Piece promotion is mandatory where promotion is legal.
Promoted pieces can demote according to the configured promotion mapping.

Winning and losing

An extinction rule is active: reaching 0 remaining piece(s) k causes a loss for the side to move.
A flag/goal-zone win is active for piece(s) p.
Stalemate is scored as a loss for the side to move.

Draws and adjudication

The n-move rule is set to 50 moves.
Position repetition is adjudicated after 3-fold repetition as a draw.

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.

Custom piece 1 (P) movement

fmWfceFifmnD

move capture move or capture initial only hopper target

Fairy-Stockfish rules

[tetrarchy]
king = -
commoner = k
rook = r
bishop = b
knight = n
queen = q
customPiece1 = p:fmWfceFifmnD
startFen = +knb+kkbn+k/pppppppp/8/8/8/8/PPPPPPPP/+KNB+KKBN+K w - - 0 1
promotionPieceTypes = -
promotedPieceType = k:q
promotionRegionWhite = *1 *2 *3 *4 *5 *6 *7 *8
promotionRegionBlack = *8 *7 *6 *5 *4 *3 *2 *1
mandatoryPiecePromotion = true
pieceDemotion = true
extinctionPieceTypes = k
extinctionValue = loss
stalemateValue = loss
flagPiece = p
flagRegionWhite = *8
flagRegionBlack = *1
nMoveRule = 50
nFoldRule = 3
nFoldValue = draw