Diplomat chess

Diplomat chess is a chess variant invented by Carlos Martin-Fuertes in 2003 as an entry to a contest for designing a chess variant playable on a board of 43 squares. The game is played on a circular board of 43 cells, including a center circle that is treated as both orthogonally and diagonally adjacent to every neighboring cell, an unusual geometry that departs sharply from the standard eight by eight chessboard. Its defining feature is a fairy piece called the diplomat, which replaces the traditional queen in each side's starting array. Rather than capturing an enemy piece outright, the diplomat can suborn an adjacent enemy piece, causing it to change sides and join the diplomat's own army, turning the familiar capture mechanic of chess into a form of in-game negotiation and conversion. The remaining pieces, pawns, rooks, bishops, knights, and the king, move in ways adapted from orthodox chess to suit the circular board, but none of them possesses the diplomat's unique suborning power. The absence of a queen and the presence of this persuasion-based piece make Diplomat chess a distinct entry among modern chess variants built around altered capture rules rather than altered piece movement alone.