After the American victory in the Guadalcanal campaign in early 1943, operations in the Solomon Islands shifted to the west, where the Japanese maintained a substantial garrison on Kolombangara.

Allied efforts to reduce these airbases initially focused on air strikes but later included naval bombardment in preparation for a ground campaign to capture New Georgia that would eventually commence in late June and early July 1943.

[6] As the Japanese ships withdrew through the Kula Gulf after landing their cargo, they encountered Task Force 68 (TF 68), consisting of three light cruisers (USS Montpelier, Cleveland, and Denver) and three destroyers (USS Conway, Cony, and Waller) commanded by Rear Admiral Aaron S. Merrill.

Two submarines, Grayback and Grampus, had been assigned to support Merrill's force and were stationed along likely Japanese withdrawal routes out of the Kula Gulf.

Meanwhile, the Japanese ships were sailing in the opposite direction along the east coast of Kolombangara, northeast from Sasamboki Island, roughly offshore from Stanmore.

In earlier naval battles in the Pacific, this tactical deficiency had allowed the Japanese to successfully engage attacking U.S. ships with torpedoes and had resulted in several losses for U.S. forces previously.

After the engagement, the U.S. vessels completed a turn to starboard when they were roughly due east of the Blackett Strait and north of Tunguirili Point.

Kagero and Oyashio sank later that day after being attacked and further damaged by U.S. aircraft from Henderson Field following a radio report from an Australian coastwatcher on Kolombangara.

[14] Later in the year, with the ground campaign around Munda reaching a climax, another engagement occurred in Blackett Strait when a force of 15 PT boats, including Lieutenant (Junior Grade) John F. Kennedy's PT-109 were sent to intercept the "Tokyo Express" supply convoy on 2 August.

[16][17] Patrolling just after the section leader had departed for home, PT-109 was run down on a dark moonless night by the Japanese destroyer Amagiri, returning from the supply mission.

Members of the destroyer crew believed the collision was not an accident, though other reports suggest Amagiri's captain had not intentionally rammed PT-109.

[20] Kennedy's crew was assumed lost by the U.S. Navy[21] but were found later by Solomon Islander scouts Biuku Gasa and Eroni Kumana.