 Heavy Japanese pressure against American forces on and around Guadalcanal—particularly the naval action that sank four Allied cruisers on the night of 8–August 9,—prompted a call for more reinforcements.Following a Japanese infantry attack along the Tenaru River on August 21, a sign that the enemy was trying to retake Henderson Field, the 7th Marines sailed from Samoa on September 4, for Espiritu Santo in the New Hebrides.Upon arrival on the 12th, the regiment received orders to move to Guadalcanal as soon as possible.