Operation Downfall order of battle

Last updated August 13, 2025

Proposed landing sites for Operation Downfall

Kyushu

Kantō Plain

Operation Downfall was the proposed Allied plan for the invasion of the Japanese home islands near the end of World War II.

The operation had two parts, Operation Olympic, intended to capture the southern third of the southernmost main Japanese island, Kyūshū, and Operation Coronet, the planned invasion of the Kantō Plain, near Tokyo, on the main Japanese island of Honshu. Olympic was scheduled for November 1945, to be followed by Coronet in early 1946.

If Downfall had taken place, it would have been the largest amphibious operation in history, surpassing D-Day.^[1] The planned operation was canceled when Japan surrendered following the atomic bombings of Hiroshima and Nagasaki, the Soviet declaration of war, and the invasion of Manchuria.^[2]

Order of Battle for Olympic

Allied

Theatre and ground force commanders
for the invasion of Japan

Gen. Douglas MacArthur

Lt. Gen. Walter Krueger

Supreme Commander, Allied Forces Pacific
General Douglas MacArthur

Ground forces

Should these four corps prove insufficient to accomplish the tasks assigned, elements earmarked for Coronet would be used to reinforce Sixth Army at the rate of three divisions per month beginning about 30 days after the initial landings.

Sixth Army

General Walter Krueger ^[3]

Peripheral landings

40th Infantry "Sunburst" Division (Landing on Yakushima and Koshikijima Islands)

158th Infantry Regiment (Landing on Tanegashima)

I Corps (Landing at Miyazaki)^[3]

Major General Innis P. Swift

25th Infantry "Tropic Lightning" Division

33rd Infantry "Illinois" Division

41st Infantry "Sunsetters" Division

V Amphibious Corps (Landing at Kushikino)^[3]

Major General Harry Schmidt, USMC

3rd Marine Division (Bougainville, Guam, Iwo Jima)

4th Marine Division (Kwajalein, Saipan/Tinian, Iwo Jima)

5th Marine Division (Iwo Jima)

XI Corps (Landing at Ariake)^[3]

Major General Charles P. Hall

1st Cavalry Division

Americal Division

43rd Infantry "Winged Victory" Division

IX Corps (Reserve afloat)^[3]

Major General Charles W. Ryder

81st Infantry "Wildcat" Division

98th Infantry "Iroquois" Division

Follow-up units:

11th Airborne Division

77th Infantry Division

Naval forces

U.S. fleet commanders

Adm. William F. Halsey

Adm. Raymond A. Spruance

Adm. Thomas C. Kinkaid

Third Fleet

Admiral William F. Halsey

20 fleet and light aircraft carriers

9 battleships

26 cruisers

75 destroyers

incl. British Pacific Fleet

6 fleet and light carriers

Fifth Fleet

Admiral Raymond A. Spruance

36 escort carriers

11 battleships

26 cruisers

387 destroyers and destroyer escorts

394 AKA, AP, APA, APD, APH

977 LSD, LSM, LST, and LSV

Seventh Fleet

Admiral Thomas C. Kinkaid

Air forces

U.S. air force commanders

George C. Kenney as a full general

Carl Spaatz as a full general

Far East Air Forces

General George C. Kenney (119,000 men) – 14 bomber groups, 10 fighter groups

Fifth Air Force

Seventh Air Force

Thirteenth Air Force

United States Strategic Air Forces in the Pacific

General Carl A. Spaatz

Major General Curtis E. LeMay ^[a]

Twentieth Air Force (Lt. Gen. Nathan Twining) (77,000 men)

1,000 B-29 Superfortresses

Eighth Air Force (Lt. Gen. Jimmy Doolittle)

Commonwealth forces

Tiger Force (detached from RAF Bomber Command):

480–580 Avro Lancaster bombers (about half to be used as tankers for in-flight refuelling)

Australian First Tactical Air Force

20 fighter/attack squadrons from the Royal Australian Air Force

Japan

Ground forces

Second General Army

Field Marshal Shunroku Hata ^[b]

Sixteenth Area Army

Lieut. General Yokoyama Isamu (600,000 men)

Northern Kyūshū — 56th Army

Lieut. General Ichiro Shichida (365,000)^[4]

145th Division

312th Division

351st Division

124th Independent Mixed Brigade

57th Division (20,000 men)

4th Tank Brigade

Southeastern Kyūshū — 57th Army

Lieut. General Nishihara Kanji (150,000 men)

Tanegashima—109th Independent Mixed Brigade (5,900 men)

Miyazaki—154th Division, 156th Division, 212th Division ^[4] (55,000 men)

Ariake—86th Division, 98th Independent Mixed Brigade, 1 regiment, 3 infantry battalions (29,000 men)

25th Division, 5th Tank Brigade, 6th Tank Brigade^[4]

Southwestern Kyūshū — 40th Army

Lieut. General Nakazawa Mitsuo (85,000 men)

303rd Division (12,000 men) (Sendai)

206th Division (Fukiage)

146th Division, 125th Independent Mixed Brigade (S. Satsuma Peninsula)

77th Division ^[4] 1 tank regiment

216th Division ^[4] 4 brigades

Air forces

Air General Army

General Masakazu Kawabe

Sixth Air Army — Kyūshū

5,000 aircraft assigned as kamikazes, 5,000 aircraft available for kamikaze service, 7,000 aircraft in need of repair

100 Koryu-class midget submarines, 250 Kairyu-class midget submarines, 1,000 Kaiten manned torpedoes, 800 Shinyo suicide boats

Order of Battle for Coronet

Allied

Ground forces

Ground force commanders
for Operation Coronet

Gen. Courtney H. Hodges as a major general

Lt. Gen. Robert L. Eichelberger

First Army

General Courtney H. Hodges ^[3]^[c]

Eighth Army

Lieut. General Robert L. Eichelberger

United States Army Forces Pacific reserve^[3]

97th Infantry "Trident" Division

Thirty days after the initial assault, each army would be reinforced by a corps of 3 divisions. Five days later an airborne division and a United States Army Forces Pacific Reserve Corps of 3 divisions would be made available. Strategic reserve for the entire operation would consist of a corps of 3 divisions located in the Philippines and divisions from the United States to permit reinforcement at the rate of 4 per month.^[3]

Unsourced listing of the aforementioned reinforcements

For First Army

Unnamed follow-on corps

5th Infantry Division

44th Infantry Division

86th Infantry Division

For Eighth Army

Unnamed follow-on corps

4th Infantry Division

8th Infantry Division

87th Infantry Division

United States Army Forces Pacific reserve

11th Airborne Division

Unnamed follow-on corps

2nd Infantry Division

28th Infantry Division

35th Infantry Division

Strategic reserve

91st Infantry Division

95th Infantry Division

104th Infantry Division

British Commonwealth Ground Forces

Commonwealth Corps (Lt. Gen. Charles Keightley)

3rd Infantry Division (United Kingdom)

6th Infantry Division (Canada)

10th Infantry Division (Australia)

Japan

Ground force commanders
for the defense of Honshu

Field Marshal Hajime Sugiyama

Gen. Shizuichi Tanaka

All Japanese formations on Honshu were badly understrength and lacking in equipment. The American First Army's landings would likely have been opposed by the Japanese 52nd Army and the Eighth Army's landings by the Japanese 53rd Army.

First General Army

Field Marshal Hajime Sugiyama ^[d]

Twelfth Area Army

General Shizuichi Tanaka ^[e]

36th Army – Urawa, Saitama

51st Army – Tsuchiura, Ibaraki

44th Division – Ogawa

151st Division – Mito

221st Division – Kashima

115th Independent Mixed Brigade – Shibasaki

116th Independent Mixed Brigade – Hokota

7th Independent Armored Brigade – Ogawa

52nd Army – Sakura, Chiba

3rd Imperial Guards Division – Naruto

147th Division – Mobara

152nd Division – Choshi

234th Division – Sōsa

3rd Independent Armored Brigade

8th Artillery Headquarters

53rd Army – Isehara, Kanagawa

84th Division – Odarawa

140th Division – Kamakura

316th Division – Isehara

117th Independent Mixed Brigade – Numazu

2nd Independent Armored Brigade – Tsudanuma

11th Artillery Headquarters – Hiratsuka

Tokyo Bay Garrison – Choshi, Chiba

321st Division – Tokyoa

Notes

↑ Running mate of segregationist presidential candidate George C. Wallace in 1968.
↑ Sentenced to life imprisonment for war crimes in 1948 but paroled in 1955
↑ Commanded First Army during Battle of the Bulge
↑ Committed suicide by gunshot following Japan's surrender
↑ Committed suicide by gunshot following Japan's surrender

References

↑ "XIII 'Downfall'". The Plan For The Invasion of Japan. United States Army Center of Military History. Archived from the original on August 17, 2019. Retrieved January 23, 2016.
↑ Giangreco, Dennis M. (2009). Hell to Pay: Operation Downfall and the Invasion of Japan, 1945–1947. Annapolis, MD: Naval Institute Press. p. xvi. ISBN 978-1-59114-316-1.
1 2 3 4 5 6 7 8 9 10 11 12 13 "Chapter XIII "Downfall" The plan for the invasion of Japan". US Army Center of Military History. Archived from the original on January 13, 2008. Retrieved 7 June 2020.
1 2 3 4 5 The majority of these units (86,000 men total) would have been ordered to counterattack at Ariake, though it is questionable how many of the tanks would have been able to survive an air attack.

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[4] Running mate of segregationist presidential candidate George C. Wallace in 1968.

[5] Sentenced to life imprisonment for war crimes in 1948 but paroled in 1955

[7] Commanded First Army during Battle of the Bulge

[8] Committed suicide by gunshot following Japan's surrender

[9] Committed suicide by gunshot following Japan's surrender

[1] "XIII 'Downfall'". The Plan For The Invasion of Japan. United States Army Center of Military History. Archived from the original on August 17, 2019. Retrieved January 23, 2016.

[2] Giangreco, Dennis M. (2009). Hell to Pay: Operation Downfall and the Invasion of Japan, 1945–1947. Annapolis, MD: Naval Institute Press. p. xvi. ISBN 978-1-59114-316-1.

[Downfall-3] 1 2 3 4 5 6 7 8 9 10 11 12 13 "Chapter XIII "Downfall" The plan for the invasion of Japan". US Army Center of Military History. Archived from the original on January 13, 2008. Retrieved 7 June 2020.

[note1-6] 1 2 3 4 5 The majority of these units (86,000 men total) would have been ordered to counterattack at Ariake, though it is questionable how many of the tanks would have been able to survive an air attack.

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[2]

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[4]

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[d]

[e]

Operation Downfall order of battle

Contents

Order of Battle for Olympic

Allied

Ground forces

Naval forces

Air forces

Japan

Ground forces

Air forces

Order of Battle for Coronet

Allied

Ground forces

Unsourced listing of the aforementioned reinforcements

Japan

Notes

References