Fog Of War

To introduce the concept of fog of war, this variant would require the use of a server delaying moves and information: when a stone is placed, it generates a diamond-like "information ripple" that extends P (typically 1) points per move in all 4 directions with each next move: when such a ripple crosses an opponent group, then only is the opponent shown that stone and becomes visible. (a "ripple" could also be seen as the set of points at the same ManhattanDistance). The ripple could be limited to a field-of-view distance, see below.

Optionally the group to which the played stone belongs might become visible either at once or under influence of the ripple.

The ripple could be delayed for M moves (typically 0) before it would start to spread.

Playing on a position that is occupied might be forbidden or dropped; the resident stone will become visible (optionally: the area within the field of view of the stone) and the opponent will be informed of the tentative.

This instantaneous feedback (illegal move, ripple information) could itself be delayed by D (typically 0) moves. This means that the actual outcome of one's own move might not be certain before D moves (so a illegal move might not be known as such until the information has reached the player: this also means that the goban presented to the player also shows the state of freshness of each intersection).

Optionally, the "field of view" (FOV) of stones could be restricted: every stone could be made to "see" only N points (again, expressed in ManhattanDistance) far; what happens outside that range is not seen by the player until a stone is positioned inside the FOV. The geometry could be a diamond (using ManhattanDistance) or a square (or some other shape?). (axd: IMO, ManhattanDistance feels like the most elegant measure in all cases.)

JoB: Do the players "announce" their moves, i.e. does the opponent get some idea of a players move or is he completely blind?

The idea is to use a computer (the server) to keep track of who can see what and when. A referee would have a tough time. To recap, a move becomes known when a ripple reaches one's own stones AND the information has passed a delay of D moves.

Some notes

• add-on to the "fog of war" concept in PhantomGo: each side divides the complete goban into arbitrary sectors, each allocated to a team member responsible for it. moves and inter-member communications are time-delayed by the server.
• the board could be subdivided in sections that are hierarchically organised, information travelling up and down the hierarchy, with an associated time cost. on each move (?), only one instance of a sibling can transmit information up the chain; as if the information channel is limited in rate.