In good order, the Marines began deployment to the Iwo Jima beach and In the deathly silence, landed US Marines began to slowly inch their way forward inland, oblivious to the danger awaiting them. After allowing the Americans to pile up men and machinery on the beach for just over an hour, the Japanese unleashed the undiminished force of their countermeasures. Shortly after 10:00, everything from machine guns and mortars to heavy artillery began to rain down on the crowded beach, which was quickly transformed into a nightmarish bloodbath.