mobility count
A measure of how many legal moves a player has in a particular position.
Mobility count is the number of legal moves available to one player in a particular Go position. It measures the breadth of that player’s immediate choices and can be used to compare the freedom of action available to both players.
To calculate it, count playable moves that satisfy the rules, including captures and, where the ruleset permits them, passes. Exclude occupied points, suicide moves when they are prohibited, and moves forbidden by ko. The result depends on the ruleset and on whether passes, ko restrictions, and strategically irrelevant moves are included in the count.
Mobility count is different from liberty count: liberty count measures the empty adjacent points of stones or groups, whereas mobility count covers the player’s total set of legal moves in the position.