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Tinian


Digital relief map of Tinian


Tinian (145.63E 15.00N) is the third largest of the Mariana Islands, with a length of about 10.5 miles (17 km) and an area of about 50 square miles (130 km2). Unlike most of the other Marianas, it was almost flat, though there were some low hills in the southwest and near the northwest coast. The latter included the highest point on the island, Mount Lasso (564' or 172 meters), which was also the Japanese command post.

The civilian population in 1941 was about 18,000 and consisted almost entirely of Japanese and Okinawans. About 90% of the land area was under cultivation, and sugar production was sufficient to support two refineries connected to the cane fields by a narrow-gauge railroad. In addition, the island was covered with a grid of narrow dirt roads between the sugar cane fields.

Though without a good port, the island has flat terrain ideal for airfields, and the Japanese had completed one airfield at Ushi Point (two 4700 foot/1430m runways) and had three others under construction by June 1944.  The United States later based its Superfortresses here.

The Tinian Campaign

Detailed planning for the American landings on Tinian did not begin until June 1944, when detailed reconnaissance was carried out even as Saipan was being conquered. The plan called for a shore-to-shore operation using the same assault forces as the Saipan invasion. Preliminary bombardment by those aircraft and warships that could be spared from the Saipan battle began on 11 June 1944, and from 20 June these were joined by heavy artillery from 24 Corps artillery sited on southern Saipan. The preliminary bombardment included the first field trials of napalm bombs.

The best landing beaches, on the west coast at Tinian Town, also had the largest concentration of Japanese troops and were quickly ruled out. The alternatives were the Yellow beaches the northeast coast and the White beaches on the northwest coast. A reconnaissance by frogmen on 10/11 July found the Yellow beaches heavily defended, with numerous mines and fortifications and a difficult reef. The two White beaches were just 60 yards (55m) and 160 yards (150m) wide, but there were no mines or barrier reef. After initially strongly opposing the idea, Turner decided to risk a landing at the White beaches. Improvised ramps were designed to be placed by LVTs on the low cliffs at the ends of each beach to allow other LVTs to come ashore here, increasing the effective frontage. Every effort was made to ensure that landing elements would move quickly off the narrow beaches where they could immediately fan out. The plan called for fourteen waves of 24 LVTs each.

Of great concern during planning was the possibility of foul weather following the landings. The typhoon season had begun, and a major typhoon immediately following the landing would have played havoc with the logistics for the White build up. As it turned out, the first spell of bad weather did not come until five days after the landing.

On 24 July 1944, about 15,600 men of the 2 and 4 Marine Divisions came ashore under the overall command of V Amphibious Corps (Schmidt). They were opposed by 50 Regiment, a battalion of 135 Regiment, 56  Guard Force, a company of light tanks and other small units (totaling about 6200 men). The defense was marred by a bitter interservice rivalry between the commanders of 50 Regiment and 56 Guard Force. Schmidt employed a clever deception plan, involving a demonstration by 2 Marine Division off Tinian Town while 4 Marine Division came ashore across the White beaches. The demonstration went as far as embarking troops in landing craft and having them come within a mile of shore before turning back, which led the overoptimistic Japanese to believe that they had repelled the landing. The Japanese were caught off guard by the real landings, which commenced at 0800 and brought ashore three battalions in just 20 minutes. The only serious resistance was from two pillboxes that were bypassed. By 1030 bulldozers were ashore, and within an hour the first tanks were able to land. The Marines' artillery was ashore by 1415.

Three Japanese counterattacks were beaten off that night. The first, by about 600 poorly trained naval infantry against the Marines' northern perimeter, took place just after midnight and was mowed down. The Marines counted 476 bodies in front of their lines the next morning. The second, at the center, commenced at 0230 and hit the seam between two regiments, making a significant penetration and causing some brief concern before it, too, was shattered. About 500 Japanese died here. The final attack at the south was supported by five light tanks, which were quickly destroyed by Marine bazooka fire and artillery. The surviving Japanese infantry committed suicide at daybreak in spectacular fashion with the magnetic antitank mines they were carrying.

The remainder of the island was quickly overrun. The Ushi Point airfield was seized on 26 July, and Smith declared the island secured on 1 August. In fact, mopping up took another two weeks. Nevertheless, Smith considered the battle "the perfect amphibious operation in the Pacific War."

The Americans lost 389 killed and 1816 wounded. A total of 252 Japanese were taken prisoner and the rest of the garrison was wiped out, with the Americans counting over 5000 bodies. American intelligence believed there were 9000 troops on the island, creating a postwar mystery over the fate of the remaining 4000. However, historians have since concluded that there were only 6200 Japanese troops on the island.

Following the campaign, the Americans turned the island into a massive airfield complex, leveling the high ground and completing six main runways, each 8500' (2590 meters) in length, to support B-29 operations. The work required the services of an entire Seabee brigade (six construction battalions) and involved moving 11 billion cubic yards of earth and coral and using construction material equal to three Boulder Dams.

References

Gilbert (2001)

Leckie (1962)
Morison (1953)

Rottman (2002)

Tillman (2010)

Venzon (2003)



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