Saipan

Saipan, the second largest island in the Marianas, was a major Japanese base and sugar production area, complete with a fairly extensive road network and narrow gauge rail system. The island has an area of about 71 square miles (184 square km) and is about 13 miles (21 km) long. The rugged center of the island rises to a peak elevation of over 1500 feet (460 m) at Mount Tapotchau. The southern end of the island is a plateau some 200'-300' or 60 to 90 meters in elevation. Most of the island (70%) was covered with sugar cane, the rest being scrub or grasslands.

There was a large Japanese civilian population, numbering about 20,000, plus 4000 Chamorros and 100 Kanakas. The town of Garapan (145.72E 15.21N), which was the Japanese administrative center of the Marianas, had a population of 10,000, and the Japanese had developed Tanapag harbor, a reef-protected anchorage just north of Garapan. Tanapag had a depth of 20'-50' (6 to 15 meters) and the Japanese had dredged a clear channel to the anchorage and built four large piers up to 700' (210 meters) long.

Aslito airfield, on the south end of the island, dated from the 1930s and was the most important Japanese airbase between Japan and Truk. A 4380' (1335m) strip was under construction at Marpi Point on the north end of the island, and a 140' by 3875' (43m by 1180m) strip had been built at Charan Kanoa that was oriented crossways to the prevailing winds, making it usable only by very light aircraft.

Coastal defenses were still incomplete in June 1944, but included 8 6" (152mm) guns, 9 140mm guns, 8 120mm dual-purpose guns, 4 200mm mortars, and a couple of dozen concrete blockhouses and pillboxes. Not all the guns had yet been sited, and significant quantities of boat mines, barbed wire, and other material for fortifications had arrived but had not yet been put to use. Even larger quantities of construction materials had been sunk by the submarine blockade.

The Battle of Saipan

Saipan had a garrison of about 32,000 men by the time of the American invasion. The garrison commander, Saito Yoshitsugu, commanded his own 43 Division and 47 Independent Mixed Brigade, as well as a hodgepodge of smaller units that included 9 Tank Regiment. Many of Saito's formations had arrived without adequate equipment due to submarine attacks on the reinforcement convoys. In particular, 118 Regiment lost 858 men and almost all its equipment when its convoy lost five of eight ships to a submarine wolf pack (Shark, Pintado, and Pilotfish) on 4-6 June 1945. There was in addition some 6690 Navy troops on Saipan, including 800 men of the Special Naval Landing Forces. The total garrison was about twice the size of American intelligence estimates.

The American invasion force for Saipan was designated Northern Attack Force (Task Force 52) and was under the personal command of Kelly Turner, with Holland M. Smith commanding the landing force of 2 and 4 Marine Divisions from 5 Amphibious Corps. Both divisions were veteran formations, 2 Marine Division having fought at Guadalcanal and Tarawa and 4 Marine Division at Roi-Namur. Fire support was provided by two groups totaling eight battleships, eleven cruisers, and 26 destroyers. Close air support was provided by two escort carrier groups totaling seven escort carriers with 169 aircraft. Additional support was provided by the fleet carriers (Mitscher) and fast battleships (Lee) of Task Force 58. All these forces came under 5 Fleet (Spruance).

The fast carriers, which were in the vanguard of the invasion fleet, began strikes against the Marianas on the afternoon of 11 June 1944. About 36 Japanese aircraft were destroyed, and a torpedo attack on the night of 11-12 June by "Betty" bombers was repulsed with one "Betty" shot down. By nightfall on 13 June, Japanese air power on Saipan and its neighboring islands had been all but eliminated. Two night attacks on 15 June from Guam were largely broken up, the Japanese losing at least seven aircraft and inflicting no damage on the American ships.

The preliminary bombardment began on 13 June 1944 with Lee's fast battleships. The first day was largely unsuccessful, as the gunners on the fast battleships had trained for fleet action rather than shore bombardment and were firing high-velocity guns with too flat a trajectory. It did not help that the ships had to fire from long range (over 10,000 yards) because the fast battleships were considered too valuable to risk in shallow water that had not yet been swept for mines. Some 2432 16" (406mm) and 12,544 5" (127mm) shells were expended to little effect. The next day, the fast battleships were relieved by the fire support groups, whose older battleships had trained extensively for shore bombardment and carefully followed a detailed fire plan. Ranges were also much shorter, as the old battleships were considered more expendable, and some of the old battleships fired from as close as two miles (3200m) to shore. The preliminary bombardment dropped a total of nearly 12 kilotons of shells on the island.

Two underwater demolition teams began operating off the landing beaches under cover of the 14 June bombardment. These reported on water depth and reefs in the landing areas, pinpointing paths through the reefs for landing craft. To their surprise, no boat obstacles or mines were encountered. The UDTs returned that evening to blast out boat passages and ramps with high explosive charges.

Landings. Landings commenced on the morning of 15 June 1944, following a final two-hour bombardment and half an hour of air strikes. A diversion was staged off Garapan to the north, but this failed to impress Saito, who had correctly guessed that the landings would take place on the southwest coast of the island, near Charan Kanoa. The initial landings were organized into four waves, each provided with 96 LVTs launched from 64 LSTs 5500 yards offshore. Close fire support was provided by 24 LCI gunboats with 40mm cannon and 18 armored LVTs. Warships were stationed 1250 yards offshore to provide additional fire support.

The initial wave came ashore at 0844 and immediately came under heavy fire. The LVTs in particular suffered heavy casualties from Japanese artillery, which was skillfully dug in on reverse slopes overlooking the beach and had registered points throughout the landing area. Pillboxes on Afetna Point, in the center of the landing area, had survived the preliminary bombardment and laid down such heavy fire that American landing craft shied away and landed their troops elsewhere, splitting the beachhead. The landing force was subject to enfilading fire from Afetna Point and Agingan Point, at the south end of the landing beaches. All four Marine battalion commanders were wounded within a few hours, and only about half the objectives for the first day were reached. There were over 2000 casualties. However, 8000 men had come ashore within the first twenty minutes, and by nightfall some 20,000 assault troops had been landed, along with tanks and artillery.

The failure to link the two beachheads left the Marines vulnerable to defeat in detail, but the Japanese missed this opportunity by attacked both beachheads simultaneously. A concentration of about 1000 Japanese troops north of the northern beachhead was hit with 5" shells from California at 1712, but this did not prevent further probing attacks.  The main Japanese counterattack in the north came at 0300 and lasted almost three hours. Five Marine tanks finally stopped the Japanese at sunrise, assisted by cruiser and destroyer gunfire. About 700 Japanese were killed. The second counterattack, from the south, was preceded by artillery preparation and hit 25 Regiment. It was broken up by 105mm artillery fire. Marines later claimed that the Japanese mingled women and children with their ranks to create the impression that this was group of civilians attempting to surrender. The third counterattack came through the gap between the two beachheads at about 0530 and succeeded in briefly capturing the Charan Kanoa pier. The Japanese were driven out with heavy loss, but not before badly damaging the valuable pier.

By 0400 on 16 June Spruance had received word that the Japanese Fleet was coming out to do battle. Spruance consulted with Turner and Smith, and the decision was made to commit the reserve, 27 Division (Ralph Smith), at once. The division began coming ashore that evening. The Japanese staged another counterattack at 0330 the next morning by 500 troops supported by 44 tanks. Ships offshore fired star shells that brilliantly illuminated the Japanese attack, and the Marines fired on the Japanese tanks with bazookas, 37mm antitank guns, and grenades. These were joined by 75mm guns on halftracks at dawn. The Japanese tanks were annihilated, the last survivor being destroyed by 5" naval gunfire as it attempted to escape into the hills.

Less than an hour later, the Marines launched attacks of their own, which by the end of 17 June had doubled the size of the beachhead. By 1400 elements of 165 Regiment had reached Aslito airfield. The attacks were supported by the Marines' artillery, spotted by OY-1 Sentinels launched from escort carriers, while deep support continued to be supplied by warships. Some 85% of all observed artillery fire on Saipan was directed by light observation aircraft. That evening the Japanese launched air raids from Truk and Yap, damaging two landing ships and putting a bomb through the after elevator of escort carrier Fanshaw Bay. The carrier was forced to retire to Eniwetok for repairs. The Japanese lost three aircraft, while the Americans lost six aircraft from White Plains in a landing accident.

By 18 June Saito was forced to admit that he had no hope of driving the Americans into the sea. Most of his troops withdrew to a line passing through Mount Tapotchau, allowing the Marines to clear most of the southern part of the island and begin repairing Aslito field, which the Marines renamed Isely Field. The first American aircraft, P-47s from 19 Fighter Squadron and P-61s from 73 Fighter Squadron, landed here on 22 June.

Meanwhile the Battle of the Philippine Sea was being fought to the west, and most of the American amphibious fleet was withdrawn to safer waters to the east. A few transports were allowed to return and continue unloading supplies on 19 June, and the remainder of the force returned on 21 June, after the Americans had won the fleet engagement.

It took another two weeks of slowly grinding forward for the Americans to clear the remaining Japanese troops from Saipan. The Japanese staged occasional small air raids, one of which managed to damage Maryland with a torpedo on 22 June. From 21-26 June the Americans attempted to batter their way past Mount Tapotchau, and 27 Division, in the center and facing formidable defenses around "Purple Heart Ridge" and "Death Valley", began to lag behind.  Smith had been disappointed with the performance of 27 Division at Makin, and his opinion of the division is only made worse when it failed to keep up with the Marine divisions on its flanks. Smith relieved the commander of 27 Division on the evening of 24  June, kicking up a controversy that is still alive today.

On 27 June, a force of about 500 Japanese troops that had been bottled up in the southern tip of the island managed to slip past a battalion of 27 Division. The Japanese force raided Isely Field before turning north to seek Saito's command post. Instead, the Japanese ran into 14 and 25 Marine Regiments and were annihilated, at the cost of 33 Marine casualties. That same day, 2 Marine Division finally captured the summit of Mount Tapotchau.

The American attack continued to grind forward, and Garapan fell on 4 July. Two days later, Saito and Nagumo both committed ritual suicide. Most of the remaining Japanese troops, numbering over 3000, made the largest suicide charge of the war into the American lines the next morning, catching 27 Division unprepared in spite of a warning from Smith to its new commander that such an attack was likely. However, the banzai charge ending organized resistance on the island. The island was declared secure on 9 July, but small groups of Japanese soldiers continued to be hunted down until 10 August.

Mass Civilian Suicides. On 9-12 July, hundreds of Japanese civilians committed suicide, many by leaping off the high cliffs on the northern end of the island. Some of those who hesitated were shot down by holed-up Japanese troops. Life correspondent Robert Sherrod spoke with a witness of once such incident (Spector 1985):

A Japanese sniper who had been exchanging shots with a platoon of marines spotted a Japanese couple with four children out on the rocks, unable to bring themselves to make the fatal leap. "'The Jap sniper took aim. He drilled the man from behind, dropping him off the rocks into the sea. The second bullet hit the woman. She dragged herself about thirty feet along  the rocks, then she floated out in a pool of blood. The sniper would have shot the children, but a Japanese woman ran across and carried them out of range. The sniper walked defiantly out of his cave and crimped under a hundred American bullets.'"

The mass suicide was one of the most horrible incidents of the war, and it probably affected American thinking during the strategic bombing campaign against Japan by reinforcing the impression that there was no meaningful distinction between Japanese soldiers and civilians.

Estimates of the numbers killed have varied widely, but Rottman (2002) estimates there were 26,000 civilians on the island at the time of the invasion, and the Americans interned about 18,000 civilians, suggesting a figure of about 8,000 civilians killed either in the fighting or in the mass suicide.

Allied order of battle, Saipan invasion

Japanese order of battle, Saipan invasion

Consequences of the battle. Total American casualties numbered 16,525, of which 3426 were killed or missing in action. Japanese dead numbered at least 23,811, and another 1780 Japanese and Koreans were taken prisoner.

Smith considered Saipan the decisive battle of the Pacific counteroffensive. Its loss came as a great shock in Japan, precipitating the fall of the Tojo cabinet.

Christmas Raid. On 25 December 1944, Isley Field was raided by five P1Y "Frances" bombers of 501 Air Group and several Ki-67 "Peggy" bombers of 7 Air Regiment. The Japanese destroyed four B-29 Superfortresses and damaged another eleven B-29s at the cost of two P1Ys.

Climate Information:

Elevation: 676'

Temperatures: Jan 81/72, Apr 83/74, Jul 83/74, Oct 83/75, record 89/72

Rainfall: Jan 12/2.7, Apr 14/2.8, Jul 23/10.0, Oct 22/11.4 == 82.3" per annum

References

Bailey (2004)

Crowl (1959; accessed 2011-5-25)

Leckie (1962)

Morison (1953)

Pearce and Smith (1990)

Rottman (2002)

The Pacific War Online Encyclopedia © 2007, 2009-2012 by Kent G. Budge. Index

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