Hexgrid

A hex map, hex board, or hex grid is a game board design commonly used in wargames of all scales. The map is subdivided into a hexagonal tiling, small regular hexagons of identical size.

The primary advantage of a hex map over a traditional square grid map is that the distance between the center of each hex cell (or hex) and the center of all six adjacent hexes is constant. By comparison, in a square grid map, the distance from the center of each square cell to the center of the four diagonal adjacent cells it shares a corner with is greater than the distance to the center of the four adjacent cells it shares an edge with. The constant distance of a hex map is desirable for games in which the measurement of movement is a factor. The other advantage is the fact that neighbouring cells always share edges; there are no two cells with contact at only one point.

One disadvantage of a hex map is that hexes have adjacent cells in only six directions instead of eight, as in a square grid map. Commonly, cells will form continuous straight lines "up" and "down", or "north" and "south", in which case the other four adjacent cells lie "north-west", "north-east", "south-west" and "south-east". As a result, no hex cell has an adjacent hex cell lying directly "east" or "west", making movement in a straight line east or west somewhat more complicated than on a square grid map. Instead, paths in these directions, and any other path that does not bisect one of the six cell edges, will "zig-zag"; since no two directions are orthogonal, it is impossible to move forward in one direction without moving backwards slightly in the other.

Games that traditionally use the four cardinal directions, or otherwise suit a square grid, may adapt to a hex grid in different ways. For example, hexagonal chess replaces the four directions of orthogonal movement (along ranks and files) with the six directions to adjacent cells, through cell edges. The four directions of diagonal movement are likewise replaced with the six directions that lie through vertices of the cell; these "diagonal" movements travel along the edge between a pair of adjacent cells before arriving at another cell. A three-colour grid aids in visualising this movement, since it preserves the traditional chessboard's property that pieces moving diagonally land only on cells of the same colour.

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