Balance of territory
A game of Go is a contest for territory. At all stages of the game, both players keep track of the amount of territory they have secured, for positional judgment. We say that they assess the balance of territory: who has the most territory so far?
If both players have equally strong positions, i.e. they are level in the balance of power, the one who is ahead in the balance of territory has the better chances to win.
(example diagrams to be added)