Key Facts
- Duration
- 1–16 April 1943 (16 days)
- Theater
- Pacific Theater, World War II
- Japanese command
- Admirals Yamamoto and Kusaka
- Primary targets
- Guadalcanal, Russell Islands, Port Moresby, Oro Bay, Milne Bay
- Operational result
- Failed to significantly damage Allied forces or delay offensives
Strategic Narrative Overview
Between 1 and 16 April 1943, Japanese bomber and fighter aircraft conducted several massed raids against Allied shipping, aircraft, and installations around Guadalcanal, the Russell Islands, Port Moresby, Oro Bay, and Milne Bay. Although a number of Allied transports and warships were sunk, the attacks failed to inflict serious aggregate damage. Aircrews submitted exaggerated and inaccurate battle reports, leading Yamamoto to conclude the operation had succeeded and to halt it on 16 April.
01 / The Origins
Following a series of Japanese defeats—at Guadalcanal, Buna–Gona, Wau, and the Bismarck Sea—Imperial Japanese forces faced mounting Allied pressure across the South Pacific in early 1943. To halt Allied momentum and buy time to construct new defensive lines, Admiral Isoroku Yamamoto ordered a large-scale aerial counter-offensive drawing on naval air units stationed at Rabaul, Bougainville, and the Shortland Islands.
03 / The Outcome
Operation I-Go ended without meaningfully disrupting Allied offensive preparations in the South Pacific. Shortly after visiting units to offer congratulations, Admiral Yamamoto was killed on 18 April 1943 when American aircraft, acting on intercepted intelligence about his itinerary, shot down his transport over Bougainville. The operation left Japan no closer to regaining strategic initiative in the region.
Belligerents & Mobilization Analysis
Side A
1 belligerent
Isoroku Yamamoto, Jinichi Kusaka.
Side B
1 belligerent
Kinetic Engagement Axis
Scroll horizontally to view full axis. Events plotted relatively.