Duell is a two-player chess variant played with dice on a board of 9x8 squares. Players take turns moving one of their dice in order to capture their opponent's pieces, with the ultimate aim of capturing the opponent's king to win the game.
Designed by Geoffrey Hayes, it was previously published in the UK as "Conquest" and "The George v Mildred Dice Game" and in Germany as "Tactix".
The board is placed between the two players such that the eight rows of nine squares run left to right. The pieces are placed so that from left to right the following numbers appear face up: 5 1 2 6 1 6 2 1 5, with the "key piece" (equivalent to the king in chess, which has a "1" on each face) appearing in the middle and the 3s facing towards the controlling player. To ensure true fairness, each die should be of the same chirality.
Players take it in turn to move one piece the number of squares shown on the outermost face (at the start of that move) by rolling it along the direction of travel such that the uppermost number changes with each square moved. A move may optionally include a single 90-degree change in direction. Moves may not pass though existing pieces of either color.
Opposing pieces are captured by landing on the occupied square with the final move. Captures are not compulsory, and there is no penalty for not doing so when possible.
The game finishes when one of the players captures their opponent's key piece; the capturing player wins, or when a players' key piece lands in the opponents "key space" (the square initially occupied by the key piece at the start of the game, in the center of the home row).