The information provided comes from Iwo Jima, by Richard Newcomb 1982. Naval action information is from The Fast Carriers: The Forging of an Air Navy, Clark Reynolds.

Operation Detachment

• Reasons for the invasion of Iwo Jima
• strategically the island of Iwo Jima was crucial to continue B-29 raid on mainland Japan.
• The island contained 3 airstrips that the Japanese had been using for their Kamikaze attacks.
• With this island captured the Kamikazes would have to operate from Okinawa or Kyushu.
• The airfields would provide a base for escort planes on their raids with the B29s.
• Iwo Jima would provide an emergency landing strip half way from Marianas island to mainland Japan

2/19 US Marines land on Iwo Jima at 8:59A.M.. This comes after 10 weeks of bombing from carrier based planes and medium bombers. The preliminary bombardment had been the heaviest up to that point in the war. A total of 70,000 U.S. Marines available for the invasion. Against 27,000 Japanese

The operation is under the overall command of Adm. R. A. Spruance, Commander Fifth Fleet. Vice Adm. R. K. Turner is the Joint Expeditionary Force Commander and Lt. Gen. H. M. Smith, UsmC, commands the Expeditionary Troops.

• The Japanese tactics would be more of a defense in-depth. No suicide counter attacks.
• The Japanese would have built 800 pillboxes and over 3 miles of tunnels on an island that was only 8 square miles in size.
• Marines landings all but easy.
  • The volcanic ash impossible to climb through with 100 pound packs carried by the Marines.
  • The high angle of the slope made return fire very difficult during the initial landings.
  • The Japanese started a mortar barrage that began at 9:15A.M.
  • Beaches and slopes leading from the beaches all zeroed in by the Japanese gunners.
  • Anti-tank mines on the slopes effective against the LVT(landing Vehicle Tracked) that are being used to deliver the Marines ashore.
• The first objective was Mt. Suribachi located on the southern end of the island.
• Until Mt. Suribachi was taken the Japanese could fire on any position the Marines had established.
• It would be the Seabees and other support units that would have high casualties in the early stages of the invasion.
• By the end of the first day the Marines had not captured half of their original objective but they had over 30,000 troops ashore to begin moving in land with force.
• Mt. Suribachi had been isolated and cut off and part of Airfield #1 had been captured.

• The fighting up the mountain some of the most intense during the war.
• Japanese soldiers entrenched in the mountain and would have to be taken out by flame throwers and satchel charges.
• Close air support by Naval and Marine pilots sometimes only a few hundred yards from advancing Marines.
• Use of Cruisers and Destroyers for close bombardment on Japanese defenses.
• No Banzai attacks by the Japanese. This would insure it to be a long drawn out battle.
• Marines even have to resort to setting fire to the ravines with gasoline to force out Japanese.

• Intense Kamikaze attacks strike U.S. naval invasion ships.
• The carrier Bismark Sea is sunk and carrier Saratoga is also damaged.
• fighting on the island now a bitter frontal attack reminiscent of the trench warfare of WW I.
• Daily gains are measured in yards with long bitter fighting for each objective.

2/22 Marines finally have Mt. Suribachi surrounded and begin to move up the face of the mountain.

2/23 First units of Marines now at the top of Mt. Suribachi after bitter fighting.

• Patrol led by Lt. Harold Schreir raises a small flag on top of Mt. Suribachi. at 10:20 A.M.

   

• Later a larger flag is brought from an LST(Landing Ship Tank) and raised.

   

• Advancements to north now have advanced to the second airfield which is located in the center of the island.

   

• The Japanese able to soon stop the tanks with ant-tank guns and mines.
• By the end of the day the 5th had only gained 500 yards
• 3rd Marine division called in to lead the attack on the center of the Japanese line.

• This area was the strongest point of the Japanese defenses.
• Flame throwing tanks brought in to burn out the Japanese defenders in their pillboxes.
• At high casualties the movement forward by the Marines was very slow.

2/28 Marines finally occupy the high ground over looking airfield #3.

• The objectives had been achieved but a number of hills around airfield #3 were still occupied by Japanese.

2/31 Marines begin to attack hills 382 and 362A.

• Both hills were much smaller than Mt. Suribachi. the size was very misleading
• The hills had both been hollowed out and turned into huge blockhouses.
• They contained pillboxes, antitank guns and concealed artillery.
• The smaller hills besides the two in this area were given nicknames like the Turkey Knob, Meat Grinder and the Amphitheater
• Some of the most intense fighting was fought to capture hill 382

3/1 Marines finally take hill 382 now move on to capture 362A

3/2For the attack on hill 362A the Marines decide on a night attack.

• The tactics did surprise the Japanese but fierce fighting and difficult terrain delayed the hills capture until March 8th.
• Even with the Marines occupying the strategic points on the island the Japanese still continued to fight in smaller pockets.

3/4 First damaged B29 lands in Iwo Jima while fighting continues all around the island.

3/6 First P-51 begin arriving on the capture airfields to provide air support for the Marines. This also relieves Task Force 58 to begin preparations for Okinawa on 4/1.

3/8 The Japanese attempt to launch a counter attack between two Marine regiments (23rd and 24th)

• The attack was stopped because the Japanese were without artillery support and were caught in the open by the U.S. Marine artillery.
• The Japanese lost 650 men in that attack alone.

• Many Japanese are infiltrating behind the U.S. lines to disrupt communication and attack headquarters.

3/25 Last pocket of Japanese resistance was secured at Kitano Point.

• That night over 200 Japanese infiltrate behind U.S. lines
• Legend says that the Japanese commander of the island led the attack.(Gen.Kurbayashi)
• The next morning over 250 Japanese lay dead around the Marines lines.
• That was the end of the resistance and the island was declared secure on 3/26.

4/7 100 P51's now stationed on the island and are escorting B29's on raids to Japan.

Marine Casualties 23,573

Japanese Troops 1,083 POW and 20,000 est. Killed

Final Analysis of the Battle

• The Naval bombardment of only 3 days leading up to the invasion was far short than what was required. The Marines had requested 13 days of prelanding bombardment but were denied this request because of commitments to MaCarthur's campaign in Luzon.
• The U.S. had underestimated the Japanese strength on the island by as much as 70 percent.
• The change in Japanese tactics was not ever contemplated because of earlier invasions on Saipan, Tarawa and Peleliu. These all had early Banzai attacks that were easily defeated and turned the tide of each invasion. This would not be the case with Iwo Jima.
• The nature and the difficulty of the soil on the island was never examined before the invasion.
• The estimates made on the U.S. casualties was underestimated by 80 percent. 23,000 Casualties out of 70,000 Marines. Over third of the total Marines who participated in the invasion were either Killed, Wounded or suffered from Battle Fatigue.
• This would be a strong warning of what was to come with the invasion of Okinawa.