Thursday 5 March 2015

World of Tank History Section: Taking Iwo Jima, Hell on Earth

The air over Iwo Jima smells of sulphur. It was mined here since before WWII. The name of the island itself means roughly "sulphur island" in Japanese.

When war erupted in the Pacific, Iwo Jima became the home of a radar station and a Japanese garrison. General Tadamichi Kuribayashi was appointed as the commander on June 30th, 1944. Under his command, the island turned into a stronghold with underground tunnels, pillboxes, and caponiers. Additional forces were moved to the island, including the 26th Tank Regiment commanded by Colonel Takeichi Nishi with 22 Chi-Ha and Ha-Go tanks.

When Nishi arrived at Iwo Jima, he could see that the island was far too small for any maneuvers. Japanese tanks were largely used as immobile guns. The Japanese also built stone replicas of tanks to scare the Americans. The deception could only be discovered close up. The island was ready for a defense.

Key to Japanese Skies

The reinforcements were not for nothing. The island had great strategic value. After the Americans knocked Japan out of the Mariana Islands, Japan was within range of B-29 Superfortress bombers. The radar at Iwo Jima gave an early warning when Japan was about to be bombed and helped Japanese fighters intercept American bombers not only on the way to the target, but on the way back. Additionally, when refueling at Iwo Jima, Japanese bombers could reach the Mariana Islands and pay the Americans a visit.

Capturing Iwo Jima would not only punch a hole in Japanese air defences, but obtain a base for American escort fighters and damaged Superfortresses. Losing a B-29 was undesirable, as it cost half a million dollars and 11 trained airmen.

Lieutenant-General Holland Smith's corps was chosen to attack the island. The American landings began on the morning of February 19th, 1945. The first wave of attackers would be supported by LVT(A)-4 amphibious tanks, a modification of the LVT with a 75 mm howitzer in an open turret. However, the offensive started slipping from the very start. Vehicles sank in the soft volcanic terrain before even reaching shore. The Japanese did not impede the landings on the beach. They were waiting until the attackers went deep into the island, onto the minefields and ranged in positions.

After a few minutes, the Americans found themselves under machinegun, mortar, and howitzer fire from hidden fortifications, with no opportunity to entrench. Walls of foxholes dug in the soft terrain would immediately cave in. Even if an American managed to dig a big enough hole or hide in a crater, he would have to deal with sulphuric gas seeping from the ground.

The second wave contained real tanks, M4A3 Shermans. The beaches were filled with vehicles, as the terrain was too soft for even tank tracks.

A bulldozer from A company tried to clear the way, but hit a mine, then was hit three times with large caliber mortars. The bulldozer was completely destroyed. Other Shermans tried to move in as a column, but made it only 90 meters before being immobilized by a minefield. 7 hours after the landing, A company was missing 12 tanks out of 17: 7 were stuck and 5 were knocked out. Other companies also took heavy losses.

By that evening, losses surpassed all estimates, consisting of over 2000 men, dead and wounded. A more sensitive army may have stopped the operation there, but Americans back then were made from tougher stuff. By the evening they numbered 30,000, surpassing the Japanese garrison.

Fire and Armour

Shermans, especially the flamethrower versions, were invaluable when chewing through Japanese lines. Tanks suppressed machineguns with their fire, then closed in and covered pillboxes and tunnels in napalm. That is, if they could close in. The Japanese used not only anti-tank mines, but IEDs made from powerful bombs or torpedoes. Minefields were covered by machineguns and anti-tank guns. A Japanese 47 mm gun was quite obsolete by 1945, but it could still penetrate the side of an American tank at close range. Infantry also hunted tanks, both with explosives on poles and suicide bombers.

American tankers tried to improve their protection with anything they could find: steel plates, sandbags, even boards. Photos from Iwo Jima show tanks that look more like sheds with guns. In reports, tankers demanded Pershing tanks, reasoning that it is not vulnerable to 47 mm guns, pole mines, and other weapons, and the Sherman's 75 mm gun could not destroy reinforced concrete pillboxes. That came later.

Five days after the beginning of the attack, soldiers of the 5th Marine Division raised an American flag over the dead Suribachi volcano. Two hours later, it was replaced with a bigger one, but this flag was the one immortalized in Joe Rosenthal's famous photograph. The flag did not mean that the island was taken. The defending soldiers had to be cleared out meter by meter from the north part, where the main target lay: the airport capable of accepting B-29 bombers. It was only taken by February 26th. On March 4th, the first Superfortress made a successful landing on the hastily repaired landing strip.

Fighting for the island continued for another month. Even when the Americans controlled the surface, the Japanese attacked from hidden tunnels. The last attack, personally headed by General Kuribayashi, took place on the night of March 26th. Individual Japanese soldiers continued hiding in numerous caves even after Japan's surrender.

Article authors: Andrei Ulanov and Aleksandr Tomzov

  • Jig Report 4th Marine Division Iwo Jima.
  • King Report 4th Marine Division IwoJima.
  • Operations Report 4th Marine Division Iwo Jima
  • Harper, David E. Tank Warfare on Iwo Jima.
Original article available here


  1. "Losing a B-29 was undesirable, as it cost half a million dollars and 11 trained pilots."

    11 trained airmen would be more accurate.

  2. Heh, I'm surprised that no one has commented on the "Americans back then were made of tougher stuff" (not that I necessarily disagree with it, though).

    When I first read of the high losses of Shermans on Iwo, I was rather surprised, as I would have thought that they could have operated largely with impunity given the backward state of Japanese tank and anti-tank technology (essentially stuck back at 1940 capability). Has anyone done any analysis on what was the chief cause of loss? (I would have guessed now general-purpose artillery HE rounds but don't know).

    I would agree that the lack of any suitable heavy infantry support tank or even assault gun in the US arsenal hindered efforts, not only in Iwo, but (based on Cooper's book) in that the Sherman had even more problems as an infantry support tank in Europe against the Germans.

  3. I think in the Italian theater the germans did not think very highly of the americans instead they respected the canadians.
    Where their forces showed up they would expect the attack to come from.

    I think it would be an interesting topic for an article to see the major nations strengths and weaknesses as judged by the other nations.

  4. Do you have any ballistic test data on captured Japanese guns?