By early 1945, Japan’s air defenses were known to be so weak that when Gen. LeMay planned the massive March 9 bombing raid on Tokyo, he ordered that the bombers be stripped of their machine guns to make room for more bombs! Edwin P. Hoyt:
General LeMay called his wing commanders to meet at his Quonset hut headquarters on Guam. He showed them the results of the [February 26] Tokyo firebomb raid. . . . His XXI Bomber Command was going to switch to night raids.
Moreover, they were going to change their entire tactics. No more high-altitude raids. They would go in low, 5,000 to 6,000 feet, and the crews would be reduced to save weight for more bombs. . . . Japanese anti-aircraft defenses were nothing like the German, LeMay knew from his European Theater experience. He anticipated losses due to flak would be only 5 percent. . . .
Only two aircraft had been lost to flak to date because the Japanese relied on searchlights and radar, while the German flak batteries were controlled electronically. . . .
What about fighters? Somebody asked.
That would not be a problem. The Japanese had only two groups of night fighters in all the home islands, LeMay said. “That’s why I’m sending in the B-29s without machine guns or ammunition.” (Hoyt, Inferno: The Fire Bombing of Japan, New York: Madison Books, 2000, Kindle Edition, locs. 231-243)
Guess how many of the 298 bombers were shot down during the raid? Keep in mind that not only did the bombers have no machine guns, they had no fighter escorts either. So guess how many of the defenseless 298 bombers the Japanese managed to shoot down? 40? 60? 80? Nope. Try 14. That’s right: only 14 of the 298 bombers were shot down, for a loss rate of only 4.7% (Hoyt, loc. 321). And this was in a two-hour raid with the bombers flying at low altitudes over the capital city.
By the way, that bombing raid killed over 100,000 Japanese civilians, wounded another 200,000, and left over a million people homeless.