It chooses the variable with the most constraints on it, regardless of the number of remaining values.

It attempts to maximize the value assigned to each variable, aiming for the highest possible values under the given constraints.

It selects the variable that is likely to cause a failure soonest, to fail early and save computation time.

It systematically assigns values starting from the minimum available in the domain to the maximum to ensure systematic exploration of the search space.

It prioritizes variables by selecting the one with the fewest legal moves remaining, thus attempting to reduce the complexity of the search space.