Prewar submarine deployments and bastion barriers

One Cold War concept would place allied submarines around Soviet bastions to intercept submarines leaving them after war began. Soviet boats could instead depart before that barrier became an active wartime interception line. Following them would risk opening gaps in the patrol arrangement, while attacking them early would start the conflict. The open sea provides much more freedom of movement than a defended land border. Territorial waters occupy only a small part of the operational space, making prewar positioning difficult to control.