Battle of Iwo Jima

Background

By August 1944 the Marianas had fallen and B-29s based there were bombing Japan. Iwo Jima, in the Volcano Islands, lay about 660 nautical miles from Tokyo, roughly on their route. Japanese aircraft had staged through its airfields to attack Saipan, and its garrison could warn the home islands of incoming raids. In American hands it promised an emergency field for damaged bombers and a base for long-range escort fighters. The Joint Chiefs judged that it could not be bypassed; the use of poison gas was considered during planning and rejected by Roosevelt, which left a frontal assault.

The island is small: about four and two-thirds miles long, from two and a half miles to under half a mile wide, some seven and a half square miles in all. The 550-foot extinct volcano of Mount Suribachi dominates the narrow southern tip; north of it two airfields crossed a waist of loose volcanic ash, and a third was under construction on the Motoyama plateau to the north.

The landing, Operation Detachment, was planned for 20 January 1945 but slipped to 3 February and then to 19 February because of delays in the Philippines. American aircraft and ships had been striking the island since June 1944. The Marine commanders asked for ten days of preliminary naval bombardment, then nine, then four; the Navy held to three, 16–18 February, while the fast carriers raided Honshu to keep Japanese air power away.

The armies

Admiral Spruance commanded the operation, Vice Admiral Turner the Joint Expeditionary Force of 485 ships, and Lieutenant General Holland Smith the expeditionary troops. Major General Harry Schmidt's V Amphibious Corps landed the 4th (Cates) and 5th (Rockey) Marine Divisions, with Erskine's 3rd Division in reserve. Corps artillery was only two battalions of 155mm howitzers, so the fleet's guns and carrier aircraft carried much of the heavy fire support.

Lieutenant General Tadamichi Kuribayashi's command, built around the 109th Division, included Major General Senda's 2nd Mixed Brigade, Colonel Ikeda's 145th Infantry Regiment, Lieutenant Colonel Nishi's 26th Tank Regiment, which reached the island with 22 tanks after 28 were lost at sea, and naval troops under Rear Admiral Ichimaru. American intelligence expected 13,000–14,000 defenders and found about 21,000. They had at least 46 artillery pieces of 75mm or larger, including twelve 320mm spigot mortars, 65 medium and light mortars, 94 heavy anti-aircraft guns, 69 anti-tank guns and large rocket bombs.

Kuribayashi rejected a defence at the water's edge and forbade banzai charges. He built mutually supporting positions in depth, a main belt across the island and a second line in the north, to be held to the death, each man to kill ten Americans first. Men dug in sulphurous heat, a few minutes at a time in gas masks. Accounts of the tunnels differ: from 5,000 of a planned 38,000 metres of main passage to 18 of a planned 27 kilometres.

The battle

The landing, 19 February. After three days' bombardment the fleet fired again from 06:40. The first armoured amphibians touched down at 09:02 and the first troops at 09:05: the 5th Division on Green and Red beaches below Suribachi, the 4th on Yellow and Blue to the north. Terraces of loose ash up to 15 feet high bogged down vehicles and men. The Japanese held their fire until the bombardment lifted, then swept the beaches with mortars and artillery. The 1st Battalion, 28th Marines crossed the 700-yard neck by 10:35 and cut Suribachi off by nightfall. About 30,000 men were ashore that evening, at a cost of 2,420 casualties, 501 of them killed. This day is not in CDB90.

Suribachi, 20–23 February. CDB90's Suribachi (519) is Colonel Liversedge's 28th Marines against about 1,300 Army and 640 Navy troops in the volcano's caves. The regiment gained 200 yards on the first day, reached the base on the 21st and had surrounded the mountain by 16:30 on the 22nd, in rain that clogged weapons with wet ash. At 10:20 on 23 February a 40-man patrol under Lieutenant Harold Schrier raised a small flag on the crater rim; a larger one replaced it later, and Joe Rosenthal photographed that second raising. Almost 2,000 Japanese were killed or sealed in caves; the regiment lost 510.

Into the main defences, 20–24 February. CDB90's Into the Main Defenses (518) is the corps' drive north from Airfield No. 1. The 5th Division gained about 800 yards on the 20th and nearly 1,000 on the 21st; the 4th, under fire from the quarry and bluffs on the right, much less. The 3rd Division's 21st Marines entered the line on the 21st, when kamikazes sank the escort carrier Bismarck Sea and badly damaged Saratoga. Rain and surf on the 22nd nearly stopped unloading. On the 24th, after a heavy preparation, tanks and infantry crossed Airfield No. 2.

The Meat Grinder, 25 February–10 March. Not in CDB90. With three divisions abreast, the 3rd in the centre took Airfield No. 2 and Hills Peter and 199-Oboe on 27 February and Motoyama village next day, then a predawn attack at 05:00 on 7 March seized Hill 362C, which daylight assaults had failed to take. On the left the 5th Division took Hill 362A on 1 March and fought over Nishi Ridge and Hill 362B. On the right the 4th Division ground through the complex of Hill 382, the Amphitheater, Turkey Knob and Minami that Marines called the Meat Grinder; Hill 382 was overrun on 2 March, and by 6 March the division was rated at 40 per cent combat efficiency. A Japanese night counter-attack on 8–9 March left 650–800 dead. Patrols reached the north-east coast on 9 March and the Turkey Knob salient was eliminated on the 10th. The first B-29 had landed on 4 March.

Final phase, 11–26 March. CDB90's Final Phase (520, 11–17 March) covers the reduction of the last pockets: Cushman's Pocket in the 3rd Division zone and the 4th Division's eastern pocket, both finished on 16 March, when the island was declared secure at 18:00. The 21st Marines took Kitano Point, but about 500 Japanese held a gorge south of it against the 5th Division until 25 March, burned and blasted out by flame tanks, armoured bulldozers and engineers. Before dawn on 26 March some 200–300 survivors attacked the bivouacs near the west beaches; this was a planned attack, not a banzai. The capture and occupation phase was declared complete at 08:00 that day.

Aftermath

The V Amphibious Corps assault units lost 24,053 men, including 6,140 dead; with the Navy and other services the toll was 6,821 dead and about 19,200 wounded. About one in three of the Marines who landed became a casualty. Almost the whole Japanese garrison died: only 216 prisoners were taken during the battle, and the Army garrison killed 1,602 more and captured 867 in April and May. Iwo Jima is the one Pacific island landing in which total American casualties exceeded Japanese, though Japanese dead outnumbered American roughly three to one. Kuribayashi's body was never identified; he probably died in the final days. Twenty-seven Medals of Honor were awarded, half of them posthumously.

The value of the island is still argued over. Alexander records 2,251 B-29 landings carrying 24,761 crewmen by the end of the war, and P-51s flew escort from it from April. Other historians, cited by Wikipedia, judge the emergency landings to have been of limited value and the island useless as a staging or fleet base. The short preliminary bombardment was criticised at once: Bartley concluded that the Navy had not allowed itself enough time.

Nimitz's judgement that 'uncommon valor was a common virtue' and Rosenthal's photograph of the second flag-raising became the battle's lasting memorials, though the photograph was long dogged by confusion with a posed group shot taken afterwards.

Wargaming it

Iwo Jima is a puzzle for the attacker and a test of discipline for the defender. The island is small enough to game whole at battalion or company level, perhaps a 100–200-yard hex and a turn per day; at most two and a half miles wide, it keeps the board manageable. Suribachi, Hill 362C or a night of the Meat Grinder make good platoon-level skirmishes.

The defender's hidden positions, linked by tunnels so that a cleared bunker can be reoccupied, need hidden-unit rules, and the Japanese player should be scored on American casualties and time, not ground: Kuribayashi's plan only works if he resists the urge to counter-attack. The 8–9 March counter-attack and the 26 March raid show what happened when the garrison did. The American player has overwhelming naval gunfire and air support but must clear caves with tank, flame-thrower, demolition and infantry teams, and watch combat efficiency fall as leaders are lost.

The beaches reward their own rules: loose ash terraces, broaching landing craft and an enemy who waits until the bombardment lifts. Good what-ifs are the ten-day bombardment the Marines asked for, a Japanese water's-edge defence as the Navy had wanted, and committing the 3rd Marines rather than individual replacements. The corps engineers' mine map of 16 March is a ready-made scenario aid.

Maps and pictures