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, a Japanese offensive (codenamed Operation Ichi-Go) in China probed toward the B–29 and Air Transport Command bases around Chengdu 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. On December 18, LeMay launched the fire raid, sending eighty-four B–29s in at medium altitude with five hundred tons of incendiary bombs. The attack left Hankow burning for three days, proving the effectiveness of incendiary weapons against the predominantly wooden architecture of the Far East.