Why was it difficult for American forces to to defend themselves against Japanese fire?

American forces faced significant challenges in defending against Japanese fire due to several factors, including the Japanese military's use of effective tactics such as surprise attacks, infiltration, and the strategic advantage of fighting in familiar terrain. The Japanese soldiers were often highly motivated and well-trained, employing effective camouflage and stealth techniques. Additionally, American troops were sometimes hampered by inadequate intelligence and preparation for the intensity and ferocity of Japanese assaults, leading to difficulties in mounting effective defenses.