The Battle of Cape Esperance, also known as the Second Battle of Savo Island and in Japanese sources as the Sea Battle of Savo Island (サボ島沖海戦), took place on 11–12 October 1942, in the Pacific campaign of World War II between the Imperial Japanese Navy and United States Navy. The naval battle was the second of four major surface engagements during the Guadalcanal campaign and took place at the entrance to the strait between Savo Island and Guadalcanal in the Solomon Islands. Cape Esperance (9°15′S 159°42′E) is the northernmost point on Guadalcanal, and the battle took its name from this point.
On the night of 11 October, Japanese naval forces in the Solomon Islands area—under the command of Vice Admiral Gunichi Mikawa—sent a major supply and reinforcement convoy to their forces on Guadalcanal. The convoy consisted of two seaplane tenders and six destroyers and was commanded by Rear Admiral Takatsugu Jōjima. At the same time but in a separate operation, three heavy cruisers and two destroyers—under the command of Rear Admiral Aritomo Gotō—were to bombard the Allied airfield on Guadalcanal (called Henderson Field by the Allies) with the object of destroying Allied aircraft and the airfield's facilities.
Shortly before midnight on 11 October, a U.S. force of four cruisers and five destroyers—under the command of Rear Admiral Norman Scott—intercepted Gotō's force as it approached Savo Island near Guadalcanal. Taking the Japanese by surprise, Scott's warships sank one of Gotō's cruisers and one of his destroyers, heavily damaged another cruiser, mortally wounded Gotō, and forced the rest of Gotō's warships to abandon the bombardment mission and retreat. During the exchange of gunfire, one of Scott's destroyers was sunk, and one cruiser and another destroyer were heavily damaged. In the meantime, the Japanese supply convoy successfully completed unloading at Guadalcanal and began its return journey without being discovered by Scott's force. Later on the morning of 12 October, four Japanese destroyers from the supply convoy turned back to assist Gotō's retreating, damaged warships. Air attacks by U.S. aircraft from Henderson Field sank two of these destroyers later that day.

As with the preceding naval engagements around Guadalcanal and to be expected from a battle of relatively limited size, the strategic outcome was inconclusive because neither the Japanese Navy nor the United States Navy secured operational control of the waters around Guadalcanal as a result of this action, and a heavy bombardment operation against Henderson Field would be conducted soon after, causing severe destruction in the three nights between 13 and 16 October. However, the Battle of Cape Esperance provided a significant morale boost to the U.S. Navy after its disastrous defeat at the Battle of Savo Island.
Background
On 7 August 1942, Allied forces (primarily U.S.) landed on Guadalcanal, Tulagi, and Florida Islands in the Solomon Islands. The objective was to deny the islands to the Japanese as bases for threatening the supply routes between the U.S. and Australia, and secure starting points for a campaign to isolate the major Japanese base at Rabaul while also supporting the Allied New Guinea campaign. The Guadalcanal campaign would last six months.
The 2,000 to 3,000 Japanese personnel on the islands were taken by complete surprise, and by nightfall on 8 August, the 11,000 Allied troops, under the command of Lieutenant General Alexander Vandegrift, secured Tulagi and nearby small islands as well as the Japanese airfield under construction at Lunga Point on Guadalcanal, named "Henderson Field" by the Allies. Allied aircraft operating from Henderson were called the "Cactus Air Force" (CAF) after the Allied code name for Guadalcanal.

In response, the Japanese Imperial General Headquarters assigned the Imperial Japanese Army's 17th Army—a corps-sized formation headquartered at Rabaul under Lieutenant-General Harukichi Hyakutake—with the task of retaking Guadalcanal. On 19 August, various units of the 17th Army began to arrive on the island.
The threat posed by Allied aircraft prevented the Japanese from using large, slow transport ships to deliver their troops and supplies to the island, so warships were used instead. These ships—mainly light cruisers and destroyers—were usually able to make the round trip down "the Slot" to Guadalcanal and back in a single night, thereby minimizing their exposure to air attacks. Delivering troops in this manner, however, prevented most of the heavy equipment and supplies, such as heavy artillery, vehicles, and much food and ammunition, from being delivered. In addition, they expended destroyers, which were desperately needed for commerce defense. These high-speed runs occurred throughout the campaign and were later called the "Tokyo Express" by the Allies and "Rat Transportation" by the Japanese.
With their heavier concentration of surface combat vessels, their well-positioned logistical base at Simpson Harbor, Rabaul, and their victory at the Battle of Savo Island in early August, the Japanese had established operational control over the waters around Guadalcanal at night. However, any Japanese ship remaining within range—about 200 mi (170 nmi; 320 km)—of American aircraft at Henderson Field during the daylight hours was in danger of damaging air attacks. This persisted for the months of August and September 1942. The presence of Admiral Norman Scott's task force at Cape Esperance represented the U.S. Navy's first major attempt to wrest night time operational control of waters around Guadalcanal away from the Japanese.

The first attempt by the Japanese Army to recapture Henderson Field was on 21 August, in the Battle of the Tenaru, and the next, the Battle of Edson's Ridge, from 12–14 September; both failed. The Japanese set their next major attempt to recapture Henderson Field for 20 October and moved most of the 2nd and 38th infantry divisions, totalling 17,500 troops, from the Dutch East Indies to Rabaul in preparation for delivering them to Guadalcanal. From 14 September to 9 October, numerous Tokyo Express runs delivered troops from the Japanese 2nd Infantry Division as well as Hyakutake to Guadalcanal. In addition to cruisers and destroyers, some of these runs included the seaplane carrier Nisshin, which delivered heavy equipment to the island including vehicles and heavy artillery other warships could not carry because of space limitations. The Japanese Navy promised to support the army's planned offensive by delivering the necessary troops, equipment, and supplies to the island, and by stepping up air attacks on Henderson Field and sending warships to bombard the airfield.
In the meantime, Major General Millard F. Harmon—commander of United States Army forces in the South Pacific—convinced Vice Admiral Robert L. Ghormley—overall commander of Allied forces in the South Pacific Area—that the Marines on Guadalcanal needed to be reinforced immediately if the Allies were to successfully defend the island from the next expected Japanese offensive. Thus, on 8 October, the 2,837 men of the 164th Infantry Regiment from the U.S. Army's Americal Division boarded ships at New Caledonia for the trip to Guadalcanal with a projected arrival date of 13 October.
To protect the transports carrying the 164th to Guadalcanal, Ghormley ordered Task Force 64 (TF 64), consisting of four cruisers (San Francisco, Boise, Salt Lake City, and Helena) and five destroyers (Farenholt, Duncan, Buchanan, McCalla, and Laffey) under Scott, to intercept and combat any Japanese ships approaching Guadalcanal and threatening the convoy. Scott conducted one night battle practice with his ships on 8 October, then took station south of Guadalcanal near Rennell Island on 9 October, to await word of any Japanese naval movement toward the southern Solomons.

Continuing with preparations for the October offensive, Japanese Vice Admiral Gunichi Mikawa's Eighth Fleet staff, headquartered at Rabaul, scheduled a large and important Tokyo Express supply run for the night of 11 October. Nisshin would be joined by the seaplane carrier Chitose to deliver 728 soldiers, four large howitzers, two field guns, one anti-aircraft gun, and a large assortment of ammunition and other equipment from the Japanese naval bases in the Shortland Islands and at Buin, Bougainville, to Guadalcanal. Six destroyers, five of them carrying troops, would accompany Nisshin and Chitose. The supply convoy—called the "Reinforcement Group" by the Japanese—was under the command of Rear Admiral Takatsugu Jōjima. At the same time but in a separate operation, the three heavy cruisers of Cruiser Division 6 (CruDiv6)—Aoba, Kinugasa, and Furutaka, all participants in the Battle of Savo Island, under the command of Rear Admiral Aritomo Gotō—were to bombard Henderson Field with special explosive shells with the object of destroying the CAF and the airfield's facilities. Two screening destroyers—Fubuki and Hatsuyuki—accompanied CruDiv6. Since U.S. Navy warships had yet to attempt to interdict any Tokyo Express missions to Guadalcanal, the Japanese were not expecting any opposition from U.S. naval surface forces that night.
Battle
Prelude
At 08:00, on 11 October, Jōjima's reinforcement group departed the Shortland Islands anchorage to begin their 250 mi (220 nmi; 400 km) run down the Slot to Guadalcanal. The six destroyers that accompanied Nisshin and Chitose were Asagumo, Natsugumo, Yamagumo, Shirayuki, Murakumo, and Akizuki. Gotō departed the Shortland Islands for Guadalcanal at 14:00 the same day.
To protect the reinforcement group's approach to Guadalcanal from the CAF, the Japanese 11th Air Fleet, based at Rabaul, Kavieng, and Buin, planned two air strikes on Henderson Field for 11 October. A "fighter sweep" of 17 Mitsubishi A6M3 Zero fighters swept over Henderson Field just after mid-day but failed to engage any U.S. aircraft. Forty-five minutes later, the second wave—45 Mitsubishi G4M2 "Betty" bombers and 30 Zeros—arrived over Henderson Field. In an ensuing air battle with the CAF, one G4M and two U.S. fighters were downed. Although the Japanese attacks failed to inflict significant damage, they did prevent CAF bombers from finding and attacking the reinforcement group. As the reinforcement group transited the Slot, relays of 11th Air Fleet Zeros from Buin provided escort. Emphasizing the importance of this convoy for Japanese plans, the last flight of the day was ordered to remain on station over the convoy until darkness, then ditch their aircraft and await pickup by the reinforcement group's destroyers. All six Zeros ditched; only one pilot was recovered.

Allied reconnaissance aircraft from Guadalcanal sighted Jōjima's supply convoy 210 mi (180 nmi; 340 km) between Kolombangara and Choiseul in the Slot at 14:45 on the same day and reported it as two "cruisers" and six destroyers. Gotō's force—following the convoy—was not sighted. In response to the sighting of Jōjima's force, at 16:07 Scott turned toward Guadalcanal for an interception.
Scott crafted a simple battle plan for the expected engagement. His ships would steam in column with his destroyers at the front and rear of his cruiser column, searching across a 300 degree arc with SG surface radar in an effort to gain positional advantage on the approaching enemy force. The destroyers were to illuminate any targets with searchlights and discharge torpedoes while the cruisers were to open fire at any available targets without awaiting orders. The cruisers' float aircraft, launched in advance, were to find and illuminate the Japanese warships with flares. Although Helena and Boise carried the new, greatly improved SG radar, Scott chose San Francisco as his flagship.
At 22:00, as Scott's ships neared Cape Hunter at the northwest end of Guadalcanal, three of Scott's cruisers launched floatplanes. One crashed on takeoff, but the other two patrolled over Savo Island, Guadalcanal, and Ironbottom Sound. As the floatplanes were launched, Jōjima's force was just passing around the mountainous northwestern shoulder of Guadalcanal, and neither force sighted each other. At 22:20, Jōjima radioed Gotō and told him no U.S. ships were in the vicinity. Although Jōjima's force later heard Scott's floatplanes overhead while unloading along the north shore of Guadalcanal, they failed to report this to Gotō.

At 22:33, just after passing Cape Esperance, Scott's ships assumed battle formation. The column was led by Farenholt, Duncan, and Laffey, and followed by San Francisco, Boise, Salt Lake City, and Helena. Buchanan and McCalla brought up the rear. The distance between each ship ranged from 500 to 700 yd (460 to 640 m). Visibility was poor because the moon had already set, leaving no ambient light and no visible sea horizon.
Gotō's force passed through several rain squalls as they approached Guadalcanal at 30 kn (35 mph; 56 km/h). Gotō's flagship Aoba led the Japanese cruisers in column, followed by Furutaka and Kinugasa. Fubuki was starboard of Aoba and Hatsuyuki to port. At 23:30, Gotō's ships emerged from the last rain squall and began appearing on the radar scopes of Helena and Salt Lake City. The Japanese, however, whose warships were not equipped with radar, remained unaware of Scott's presence.
Order of battle
Imperial Japanese Navy
Rear Admiral Aritomo Gotō
3 heavy cruisers
1 Furutaka-class: Furutaka (sunk)
2 Aoba-class: Aoba (heavily damaged), Kinugasa
Top speed: 33 knots
Main battery: 6 × 8-inch
Secondary battery: 4 × 4.7-inch
Anti-aircraft battery: 8 × 25mm, 4 × 13mm
Torpedo tubes: 8 × 24-inch
2 destroyers
Both Fubuki-class: Fubuki (sunk), Hatsuyuki
Top speed: 34 knots
Main battery: 6 × 5-inch
Anti-aircraft battery: 2 × 13mm
Torpedo tubes: 9 × 24-inch
United States Navy
Rear Admiral Norman Scott
2 heavy cruisers
1 New Orleans-class: San Francisco
Top speed: 32.7 knots
Main battery: 9 × 8-inch guns
Secondary battery: 8 × 5-inch/25-cal. dual-purpose
1 Pensacola-class: Salt Lake City (damaged)
Top speed: 32.7 knots
Main battery: 10 × 8-inch guns
Secondary battery: 8 × 5-inch/25-cal. dual-purpose
2 light cruisers
Both Brooklyn-class: Boise (heavily damaged), Helena
Top speed: 34 knots
Main battery: 15 × 6-inch guns
Secondary battery: 8 × 5-inch/25-cal. dual-purpose
5 destroyers
3 Gleaves-class: Buchanan, Duncan (sunk), McCalla
2 Benson-class: Farenholt (heavily damaged), Laffey
Top speed: 37 knots