On 12 March 1944, the Commander in Chief, Pacific Ocean Areas, Admiral Chester W. Nimitz, was directed to neutralize Truk and occupy the Mariana Islands.

Following the conclusion of the Battle of Saipan on 9 July, Major General Harry Schmidt's V Amphibious Corps began preparations to invade nearby Tinian.

Major General Clifton B. Cates's 4th Marine Division landed on Tinian on 24 July 1944, supported by naval bombardment and the guns of the XXIV Corps Artillery, firing across the strait from Saipan.

These beaches were flanked by low coral cliffs that the marines were able to surmount with the aid of ramps mounted on modified amphibious tractors (LVTs).

A successful feint in the southwest by Major General Thomas E. Watson's 2nd Marine Division distracted defenders from the actual landing site on the north of the island.

At the Casablanca Conference in January 1943, the US and British Combined Chiefs of Staff had endorsed an offensive in the Central Pacific along the lines envisaged in the Orange plans.

[5] The Combined Chiefs endorsed this at the Cairo Conference in December, along with a two-pronged offensive, with the Central Pacific drive in conjunction with one along the north coast of New Guinea.

[9] By February 1944, there was consideration of advancing the Operation Granite timetable by bypassing Truk and heading directly for Palau or the Marianas after the capture of the Marshall Islands.

Although Turner and Smith remained in command of Task Forces 51 and 56 respectively, they sailed for Guam on 20 July, leaving the operation entirely in the hands of Hill and Schmidt.

The staff of the 4th Marine Division, particularly the plans officer, Lieutenant Colonel Evans F. Carlson, preferred to land in the north, where the beaches were poorer but the defenses were weaker and tactical surprise could be attained.

"[58] Turner noted that the Sunharon Bay beaches had good gradients and inland approaches, that there was a protected harbor for small craft, and facilities for unloading supplies.

Whereas the northern beaches were too small to land and support a force of the size contemplated, and were exposed to the weather, so if it turned bad the movement of supplies from Saipan could be obstructed or halted.

Yellow Beach 1 was found to be strung with a double apron wire obstacle, with cliffs to the south that were 20 to 25 feet (6.1 to 7.6 m) high and unscalable without ladders or cargo nets.

[69] The US naval bombardment commenced on 13 June, with the fire support ships of Task Force 52 engaging targets on Tinian that could interfere with operations on Saipan.

[70] The battleship USS Colorado engaged the three 140 mm coast defense guns at Faibus San Hilo Point, which could enfilade the White Beaches from defilade of the artillery on Saipan.

[72] Attempts by destroyers to burn wooded areas with white phosphorus and thermite on 18 and 19 July failed due to the wet foliage, so napalm was tried for the first time.

[74] While covering the feint, Colorado and the destroyer Norman Scott were hit by the three Japanese 6-inch guns, which were concealed in caves 3,500 yards (3,200 m) southwest of the Tinian Town pier.

[79] The marines left their packs behind on Saipan and landed with coveralls, M1 helmets with camouflage covers, weapons, emergency rations, a spoon, a spare pair of socks, a poncho and insect repellent.

[92] As they moved north along the coast through terrain characterized by coral rocks and thick undergrowth, the 1st Battalion, 8th Marines, was held up by a force of 20 to 25 Japanese that it took until 11:30 to overcome.

The advance had now begun to outrun the range of the artillery on Saipan, so the 105 mm howitzer battalions of the 10th and 14th Marines displaced to Tinian on 26 and 27 July and rejoined their divisions.

[99][100] With the Ushi Point airfield in American hands, the 121st Naval Construction Battalion commenced its repair on 27 July, filling in the bomb and shell craters.

[102] Hill summoned the 9th Troop Carrier Squadron from Eniwetok and its Douglas C-47 Skytrains, together with the Curtiss C-46 Commandos of VMR-252, delivered 33,000 rations from Saipan on 31 July.

[109][110] As they advanced, the marines encountered civilians waving white cloths, who had to be approached with care, as sometimes one of their number turned out to be a Japanese soldier intent on suicide and taking some Americans with him.

Although also penetrated, it too remained operational, and this time the target was spotted, and engaged by tanks that destroyed the gun and machine-gunned twenty Japanese crewmen who tried to escape.

Engineers removed the mines, allowing tanks to proceed up the road and destroy Japanese positions, while the accompanying infantry battled their way through the brush.

[126] The operation was much less difficult than Saipan; the nearest base was just 5 miles (8.0 km) away, not over a thousand; the garrison was smaller; the ratio of attackers to defenders was greater; the terrain was less formidable; intelligence was more accurate; and the preliminary naval and aerial bombardment more protracted.

Heavier American casualties might have been inflicted by a passive defense, taking advantage of their skill with camouflage, use of terrain, and emplacement of weapons, but this was not Japanese doctrine at the time.

[138] The garrison on Aguiguan Island off the southwest cape of Tinian, commanded by Second Lieutenant Kinichi Yamada, held out until the end of the war, surrendering to Rear Admiral Marshall R. Greer on the United States Coast Guard Cutter USCG 83525 on 4 September 1945.

[145] Journalist Robert Sherrod noted that most died as a result of the fighting; the Americans made great use of artillery, aerial and naval bombardment, and civilians often sheltered with soldiers.

The adjacent base for naval aircraft had 16,000 feet (4,900 m) of taxiways, 70 hardstands, 345 Quonset huts, 33 administration, maintenance and repair buildings, and a 75-foot (23 m) tall control tower.