 As December began , the Japanese experienced considerable difficulty in keeping their troops on Guadalcanal resupplied because of Allied air and naval attacks on the Japanese supply chain of ships and bases . The few supplies delivered to the island were not enough to sustain Japanese troops , who by 7 December were losing about 50 men each day from malnutrition , disease , and Allied ground or air attacks . The Japanese had delivered almost 30 @,@ 000 army troops to Guadalcanal since the campaign began , but by December only about 20 @,@ 000 of that number were still alive , and only about 12 @,@ 000 remained more or less fit for combat duty , with the rest incapacitated by battle wounds , disease , or malnutrition . 
