Mask search is an optimization process in neural network pruning used to identify an optimal selection mask that determines which network components, such as individual weights, channels, or attention heads, should be retained or removed. Rather than discarding parameters arbitrarily, a mask search evaluates the importance or sensitivity of different model components based on statistical, gradient, or informational metrics to find a sparse subnetwork configuration. This search operates under specified computational or memory budgets, enabling deep learning models to reduce latency and resource overhead while preserving baseline accuracy and task performance.