Irrelevant move

An irrelevant move or wasted move is a move that does not improve the position of the player who makes the move. It is considered as a waste of time and should be avoided.

Any move in a dead cell is irrelevant. An example of this is the useless triangle. If a player plays in a dead cell, the opponent does not have to respond, i.e., the situation is as if the player had passed.

Another example of an irrelevant move is a move in a cell that is already captured by the same player. Such moves can also be ignored by the opponent, i.e., they are equivalent to passing.

A move in a cell that is captured by the opponent is also an irrelevant move, but sometimes the opponent is forced to respond to maintain the capture. While such a move does not improve the position of the player who makes it, it can sometimes happen that it does not improve the opponent's position either. Thus, the effect of such a move is in the best case neutral for the player who makes it. However, if the opponent has a better response available, such a move can still hurt the player who makes it.

Any move that the opponent can kill with the next move is also irrelevant, as it doesn't help the player and may help the opponent.

A move that does not interfere with any of the opponent's threats is also irrelevant.

An irrelevant move that is also forcing can sometimes be used as a time tesuji, i.e., a move that is played to manage the game clock. If the time controls include an increment (for example, 30 seconds per move), then a player who is low on time could make an irrelevant move that forces a response in order to get more time on their clock without changing the game situation. This is risky, though, as the opponent could potentially find a better response.

Examples

Red to move.

A red move at c2 would be irrelevant because it is in a useless triangle (therefore dead). A red move at e1 would be irrelevant because e1 is also dead. A red move at d6 would be irrelevant because d6 is already captured by Red. A red move at f3 would be irrelevant because f3 is already captured by Blue. Blue could in principle respond at f4 to kill f3, showing that f3 had no possible benefit for Red. (However, it is much better for Blue to instead respond at e3, which is winning for Blue, unlike f4, which is losing). A red move at b5 would be irrelevant because it is not in the path of any of Blue's threatened connections.