200 rocket launchers
10,000 rifles
Though the 320-millimeter spigot mortar was bizarre—its 675-pound shell bigger than the firing cylinder and fitting over and round it, its life no more than half a dozen rounds, its erratic projectile feared as much by its crew as by its intended victims—it could nevertheless make a monster bang. And when 60,000 Marines became packed onto tiny Iwo Jima, it would be difficult for it to be harmless. The rockets, varying in size from 550 to 200 pounds, were likewise more noisy than nasty. But the rest of that fearful armament could have ferocious effect, and Kuribayashi had emplaced these guns in an elaborate system of caves and concrete blockhouses.
Where Peleliu had 500 caves, Iwo Jima had 1,500—most of them on the Motoyama Plateau rising north of Airfield Number One. Where Tarawa had blockhouses and pillboxes of ferro-concrete, Iwo Jima also had them— five-foot walls, ten-foot ceilings, sandbagged, humped around with 50 feet of sand and piggy-backed with machine-gun turrets—but Iwo Jima also had them invisible. Tarawa’s had been above ground, for the water level was only four feet. Iwo had no bottom, and up in the north it had a tunnel system surpassing the Umurbrogal’s. Kuribayashi had already set his men to work digging the first links of an underground network to total some 30 miles. Construction was around the clock. Every man worked three hours on, five off, or as long as was necessary to dig a minimum three feet. They worked wearing gas masks to filter out the fumes from Iwo’s numerous sulphur wells. Some places were so hot with sulphur that the men could cook a pan of rice over them in twenty minutes. But Kuribayashi got only about four miles of this master tunnel system finished before the Marines came, although he still had many miles of completed tunnels and interconnected caves below the ridges and among the rocky gorges of the two cross-island defense systems he had completed in the northeast.
The first of these two barriers was the main one. It began on the Motoyama Plateau about a mile northeast of Airfield Number One and the narrow ashen neck on which Kuribayashi hoped to annihilate the Americans. Both of its flanks were on the sea and its center was anchored on Airfield Number Two, located at almost the exact middle of the island. This line was actually a belt of mutually supporting positions about 1,000 yards in depth, southwest- to-northeast. The second line, not as deep or as formidable, began a mile or so northeast of the first. The second line’s flanks were also on the sea, while uncompleted Airfield Number Three, a mile directly northeast of Airfield Number Two, represented its center. Behind the second line, in the last mile or so of northeastern Iwo, were more defenses—all made menacing by fantastic terrain. Such terrain could conceal the communications center located just south of Kita. It was a fortress with five-foot walls and ten-foot roof, a single room 150 feet long and 70 feet wide, housing 20 radios, reached only by a 500-foot tunnel about 75 feet underground—the tunnel’s entrance cleverly hidden between two small hills.
Nor would the gunners popping out of this monster Chinese-box of a defense be the usual bad shots the Marines had encountered across the Pacific. Kuribayashi made sure of this in training characterized by this order:
“It is necessary to eliminate completely the idea that firing results are satisfactory if shells merely fall in the enemy area. We must without fail score direct hits on the targets.”
The general was also that rare thing among Japanese officers he was security-conscious. He set up eight different defense sectors, each with a plan of its own, none aware of the others’. If the Bushido code made it impossible for Kuribayashi to instruct his men on what to say when captured, he could at least guard against the inevitable by giving them nothing to talk about. There were also plans for defense against possible airborne attack, for the destruction of roads, for the digging of numerous ditches to guard against the American tanks Kuribayashi feared so much, and, finally, for encouraging the troops to disregard the devastating aerial and surface bombardment which preceded the American attacks.
“We must strive to disperse, conceal, and camouflage personnel, weapons and materiel, and make use of installations to reduce damage during enemy bombing and shelling. In addition we will enhance the concealment of various positions by the construction of dummy positions to absorb the enemy shelling and bombing.”
All this was done. Even the firing ports of the pillboxes were made small and angled so that nothing could enter them but a grenade thrown from a few feet away or a hand-gun fired point-blank. If this cut down the field of fire, it made little difference—there were so many pillboxes supporting each other.
When the Seventh Air Force launched its seventy-two day pounding of Iwo Jima, Kuribayashi’s men stayed out of sight and dug their ditches all the deeper.
When the long thick shapes of the American bombardment ships slid out of the darkness on the morning of February 16, the Japanese refused to be goaded into firing back and giving away the position of the coastal guns. Even though they had smokeless powder, they refused. Only when the swimmers of the Underwater Demolition Teams came into the eastern beaches on February 17 did they open up. They thought the invasion had begun, and big guns on the cliffs to the north began shooting at the covering gunboats. It was their only mistake and they paid for it dearly. Those vital guns were knocked out and left dangling down the cliff faces.
Otherwise, Lieutenant General Tadamichi Kuribayashi calmly observed the destruction of pillboxes on the eastern beaches and heard reports of the gradual loss of much of his communications. He had expected the last, and had prepared for the first. The Americans would come ashore thinking his armor knocked out. Their planes would fly away. Their naval gunfire would lift. They would see only the terraces of volcanic ash which sea and wind had piled a few dozen yards inland at heights up to 15 feet. They would struggle beyond these. Then they would see the flatland with its hummocks of sand.
But the hummocks would turn out to be hidden guns and the armor supposedly knocked out would begin the slaughter already celebrated in the Iwo Jima Garrison Song.
