The Battle of Iwo Jima
1945 Pacific Theater
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.
Reasons for the invasion of Iwo
- 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.
2/20 Marines start their advance south to Mt. Suribachi and
north to the airfields.
- 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
- 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.
2/21 Marines continuing their advance North and South on the
- The fighting up the mountain some of the most intense during
- 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
- 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
- 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
2/24 4th and 5th Marines attack after a 76 minute naval
bombardment. Followed by an air strike and supporting artillery.
It would be the tanks that led the way for both divisions.
- 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.
2/25 3rd Marine division begins attack on the center of the
Japanese line at 9:30 A.M.
- The Japanese able to soon stop the tanks with ant-tank guns
- 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
2/28 Marines finally occupy the high ground over looking airfield
- 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
- They contained pillboxes, antitank guns and concealed
- 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
3/1 Marines finally take hill 382 now move on to capture 362A
3/2 For the attack on hill 362A the Marines decide on a night
- 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)
3/15 resistance continues in many small pockets located on the
- The attack was stopped because the Japanese were without
artillery support and were caught in the open by the U.S. Marine
- 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
- That night over 200 Japanese infiltrate behind U.S. lines
- Legend says that the Japanese commander of the island led
- The next morning over 250 Japanese lay dead around the
- 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.
U.S. personnel 6,821 Killed 19,217
Wounded 2,648 Combat Fatigue Total 28,686
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.