On August 7th, while the main US force was engaged on Tulagi, Marine paratroopers from the 1st Parachute Battalion landed on the north shore of Gavutu with support from Fire Group Mike at 1130 hours. They faced stiff resistance from Japanese units from the 3rd Kure Special Naval Landing Force (SNLF) and the Yokohama Air Group. The Axis forces had a service platoon on the top of the hill on Tanambogo protected by an SNLF unit in a cave below, a 75mm howitzer platoon on the eastern point of Gavutu, and an SNLF HMG unit with two service platoons in a cave on the southern tip of Gavutu. There were also three service units and a 37mm AA platoon hidden on the two islands. A squadron of SBD’s dispatched the pesky Axis 75mm unit before noon, but then a thunderstorm broke out slowing movement on Gavutu for half an hour. When the sun came back out, service troops were spotted scurrying into one of the south caves so the troops from A & B Companies set up a perimeter. As C Company reinforcements landed, Major Conforti and his causeway para group eliminated the recently discovered 37mm AA platoon on the northeast shore of Tanambogo. By 1430 hours, one service platoon has been expelled from its cave and was eliminated. The other cave on Gavutu held both service platoons and a SNLF HMG group, so the paras held the perimeter until the reinforcements from Company B, 1st Battalion, 2nd Marine Regiment arrived. A combined arms group from that regiment then assaulted the remaining cave on Gavutu, but was repelled. After regrouping, they stormed the cave again and eliminated the remaining Japanese troops, securing Gavutu by 1700. A brief attempt was made to cross the causeway before dark, but the strike force was quickly disrupted by heavy fire from Japanese troops emerging form the cave on the south end of Tanambogo. So, the newly arrived M5 took point on the east end of the causeway, while the remainder of the Allied forces spent the night in relative quiet. When dawn broke, the Marines reassembled and assaulted the cave at the base of the hill on Tanambogo at 0600 hours. They forced the Japanese service/SNLF group to flee to the top of the hill and eliminated them shortly thereafter. By 0645 hours, both islands were free of Japanese troops and secured for an Allied victory.

This scenario was played using 4th edition rules (including the updated cave rules), and the special rules regarding Hidden Units (#4) from the Kokoda Campaign scenario book. It basically requires the Japanese to eliminate at least 7 American steps, while the Americans must clear the Japanese from the island while not losing more than six steps. The early turns broke well for the Marines since they were able to identify most of the hidden units quickly with some fortuitous hits. The early elimination of the 75mm artillery unit also was a great break. Much of the early game after that involved waiting for the Marine HMG support to help in the cave assaults. The initial morale check of the paras worked out well with only one disruption, and they were able to secure most of Gavutu except for the caves, which were then cleared later on with a loss of two steps. After the night break, the Tanambogo cave was cleared as the Marines rolled a two-step loss on the second assault and drove the disrupted Japanese units out in the open, where they were quickly dispatched. The Japanese have two options, to either confront the paras and hope for some quick step losses, or to hold out in the caves where they have an advantage with the automatic 2-column shift. This scenario used the latter approach, but the quick discovery of the hidden units compromised the Axis firepower. The cave assaults have the potential to be brutal for either side, but the Marines clearly had the best of those actions. The scenario went a total of 88 turns, but the Japanese have little to do on many of them, similar to the Marines at night. The Japanese lost 18 steps to the three lost by the USMC, and it was an American victory.