While planners assessed this option, the Anglo-American Combined Chiefs of Staff, meeting in Quebec in August, authorized a central Pacific drive that included the seizure of the Marianas.

However, President Franklin D. Roosevelt decided in favor of the China bases because he was impatient to bomb Japan and wished to bolster the Chinese war effort.

Meanwhile, 1,000 miles to the northeast, across the Himalayan mountains, about 350,000 Chinese workers toiled to build four staging bases in western China near Chengtu.

[2] A committee of operations analysts who advised the Joint Chiefs of Staff and the Twentieth Air Force on targets recommended Superfortress attacks on coke ovens and steel factories in Manchuria and Kyūshū.

[3] Ten days later, sixty-eight Superfortresses took off at night from staging bases at Chengtu to bomb the Imperial Iron and Steel Works at Yawata on Kyūshū, more than 1,500 miles away.

Each B–29 mission consumed tremendous quantities of fuel and bombs, which had to be shuttled from India to the China bases over the Himalayas, the world's highest mountain range.

[3] Targets in South East Asia also involved lengthy flights, with the Operation Boomerang raid which was conducted against Palembang on 10/11 August requiring a round trip of 3,855 miles (6,204 km).

Also, the Twentieth Air Force periodically diverted the Superfortresses from strategic targets to support theater commanders in Southeast Asia and the southwestern Pacific.

The youngest two-star general in the Army Air Forces had also revised tactics, tightened and expanded formations, and enhanced training for greater bombing precision.

He inaugurated a lead-crew training school so that formations could learn to drop as a unit on cue from the aircraft designated as the lead ship.

When Douglas MacArthur invaded the Philippines in October 1944, LeMay diverted his B-29s from bombing Japanese steel facilities to striking enemy aircraft factories and bases in Formosa, Kyūshū, and Manchuria.

Willing to help against a common enemy, Mao agreed to assist downed American airmen and to locate in northern China a weather station that would provide better forecasts for the XX Bomber Command's raids on the Japanese in Manchuria and Kyūshū.

[3] The former European theater bomber commander continued to experiment with new technologies and tactics and soon imported to China the incendiary weapons being used by the British against Germany.

In late 1944, Japanese offensive (codenamed Operation Ichi-Go) in China probed toward the B–29 and Air Transport Command bases around Chengtu and Kunming.

To slow the enemy advance, Maj. Gen. Claire L. Chennault of the Fourteenth Air Force asked for raids on Japanese supplies at Hankow, and the Joint Chiefs directed LeMay to hit the city with firebombs.

[3] By late 1944, American bombers were raiding Japan from the recently captured Marianas, making operations from the vulnerable and logistically impractical China bases unnecessary.