Orders of battle for Downfall



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. 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.

Allied
 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.


 * US Sixth Army patch.svg  Sixth Army 
 * General  Walter Krueger 
 * Peripheral landings
 * 40th Infantry Division CSIB.svg 40th Infantry "Sunburst" Division (Landing on Yakushima and Koshikijima Islands)
 * 158th Inf DUI.jpeg 158th Infantry Regiment (Landing on Tanegashima)
 * US I Corps.svg I Corps (Landing at Miyazaki)
 * Major General Innis P. Swift
 * 25th Infantry Division CSIB.svg 25th Infantry "Tropic Lightning" Division
 * 33rd Infantry Division SSI.svg 33rd Infantry "Illinois" Division
 * 41st Infantry Division SSI.svg 41st Infantry "Sunsetters" Division
 * USMC V Amphib Corps.png V Amphibious Corps (Landing at Kushikino)
 * Major General Harry Schmidt, USMC
 * US 3d Marine Division SSI.svg 3rd Marine Division (Bougainville, Guam, Iwo Jima)
 * 4THMARDIV.svg 4th Marine Division (Kwajalein, Saipan/Tinian, Iwo Jima)
 * US 5th Marine Division SSI.svg 5th Marine Division (Iwo Jima)
 * US XI Corps SSI.svg XI Corps (Landing at Ariake)
 * Major General Charles P. Hall
 * 1st Cavalry Division SSI (full color).svg 1st Cavalry Division
 * Americal patch.svg Americal Division
 * 43rd Infantry Division CSIB.svg 43rd Infantry "Winged Victory" Division
 * IX Corps insignia.gif IX Corps (Reserve afloat)
 * Major General Charles W. Ryder
 * US 81st Infantry Division.png 81st Infantry "Wildcat" Division
 * 98th Infantry Division shoulder sleeve insignia.svg 98th Infantry "Iroquois" Division
 * Follow-up units:
 * 11th Airborne Division.patch.png 11th Airborne Division
 * 77th Infantry Division.patch.jpg 77th Infantry Division

Naval forces

 * 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

 * 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
 * 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

Ground forces

 *  Second General Army 
 * Field Marshal Shunroku Hata
 * Sixteenth Area Army
 * Lieut. General Yokoyama Isamu (600,000 men)
 * Northern Kyūshū — 56th Army
 * Lieut. General Ichiro Shichida (365,000)
 * 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 (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
 * 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 1 tank regiment
 * 216th Division 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

Ground forces

 * 1st Army.svg First Army
 * General Courtney H. Hodges
 * USMC III Phib Corps Large.png III Amphibious Corps
 * US 1st Marine Division SSI.svg 1st Marine Division (Guadalcanal, Peleliu, Okinawa)
 * 2nd Mar Div;divlogo1.png 2nd Marine Division (Tarawa, Saipan, Okinawa)
 * 6th MarDiv.png 6th Marine Division (Okinawa)
 * XXIV Corps SSI.gif XXIV Corps
 * 7th Infantry division Shoulder Sleve insignia.png 7th Infantry "Bayonet" Division
 * 27th Infantry Division SSI.svg 27th Infantry "New York" Division
 * 96th Infantry Division SSI.svg 96th Infantry "Columbia" Division
 * Eighth United States Army CSIB.svg Eighth Army
 * Lieut. General Robert L. Eichelberger
 * X Corps SSI.gif X Corps
 * 24 Infantry Division SSI.svg 24th Infantry "Taro" Division
 * 31st ID SSI.svg 31st Infantry "Dixie" Division
 * 37th Infantry Division CSIB.svg 37th Infantry "Buckeye" Division
 * US XIV Corps patch.svg XIV Corps
 * 6th Infantry Division.svg 6th Infantry "Red Star" Division
 * 32nd infantry division shoulder patch.svg 32nd Infantry "Red Arrow" Division
 * 38th Infantry Division SSI.svg 38th Infantry "Cyclone" Division
 * USA - XIII Corps.png XIII Corps (Reserve afloat)
 * 13th US Armored Division SSI.svg 13th Armored Division
 * 20th US Armored Division SSI.svg 20th Armored Division
 * United States Army Forces Pacific reserve
 * 97THID.svg 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.

Unsourced listing of the aforementioned reinforcements

 * For First Army
 * Unnamed follow-on corps
 * US 5th Infantry Division.svg 5th Infantry Division
 * 44 INF DIV SSI.svg 44th Infantry Division
 * 86 Inf Div SSI.jpg 86th Infantry Division
 * For Eighth Army
 * Unnamed follow-on corps
 * Insignia USA Army 4th Infantry Division SSI.svg 4th Infantry Division
 * 8th Infantry Division patch.svg 8th Infantry Division
 * US_87th_Infantry_Division_2.png 87th Infantry Division
 * United States Army Forces Pacific reserve
 * 11th Airborne Division.patch.png 11th Airborne Division
 * Unnamed follow-on corps
 * 2nd Infantry Division SSI (full color).svg 2nd Infantry Division
 * 28th Infantry Division SSI (1918-2015).svg 28th Infantry Division
 * 35th Infantry Division SSI.svg 35th Infantry Division
 * Strategic reserve
 * US 91st Infantry Division.svg 91st Infantry Division
 * 95TrainingDivSSI.jpg 95th Infantry Division
 * 104TrngDivLdrTrngSSI.svg 104th Infantry Division
 * British Commonwealth Ground Forces
 * Commonwealth Corps (Lt. Gen. Charles Keightley)
 * British 3rd Infantry Division2.svg 3rd Infantry Division (United Kingdom)
 * 6 Canadian Infantry Division patch.svg 6th Infantry Division (Canada)
 * 10th Div 2nd AIF.png 10th Infantry Division (Australia)

Japan
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
 * Twelfth Area Army
 * General Shizuichi Tanaka
 * 36th Army – Urawa, Saitama
 * 81st Division
 * 93rd Division
 * 201st Division
 * 202nd Division
 * 206th Division
 * 214th Division
 * 1st Tank Division
 * 4th Tank Division
 * 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