By the summer of 1945 there simply put was NO Japanese air force left in any effective manner. Squadrons had been withdrawn to caves and hidden hideouts to serve as suicide attacks when the invasion came. And AAA batteries had been concentrated around Tokyo, and even then by the summer ammunition was running dry and rationed for the coming invasion.

The B-29 also had a service ceiling that was right up against or a bit over most Japanese fighters at over 30k ft. The USN had also spent the entire summer with the carrier task force standing off the home islands and systematically destroying targets of military value, to the extent even that battleships sailed into range and fired on coastal targets with their guns. The eroded state of Japanese air defenses by August 1945 is something that should be stressed.

Curtis Le May even was quoted as saying in July 1945, "it was safer to fly a combat mission over Japan than it was to fly a B-29 training mission back in the United States"

from your post in the other tread but reposted here for more visibility.

A good book i read years ago on the topic was Closing the Circle: War in the Pacific, by Edwin Hoyt

The [linked article in the other thread] (http://ww2db.com/battle_spec.php?battle_id=49) is correct that several small raids were made in July and August, but to say "the purpose of such flights were to wear down the alertness of Japanese anti-aircraft defense crew" isn't entirely accurate.

The raids were carried out by the unit formed to drop atomic weapons, the 509th Composite Group, using "pumpkin" bombs that simulated the size and weight of the Fat Man atomic bomb. To gather data and gain experience the 509th first flew training flights around outlying islands such as Rota and Marcus Island, then from July 20th there were 18 bombing sorties of two to six Silverplate B-29s against targets in Japan, starting with Koriyama, Fukushima, Nagoka and Toyama.

As others mention in this & the other thread, Japanese air defences were all but destroyed by this point; only the heaviest anti-aircraft guns were effective against B-29s flying at 30,000ft and these were in short supply. The 509th suffered no losses during the "pumpkin" missions, only one B-29 suffered minor damage.

One of the goals/benefits of the missions was that small groups of B-29s on bombing missions (the 3rd Photo Reconnaissance Squadron had been flying over Japan in F-13As, the reconnaissance version of the B-29, from late 1944) were not sufficiently unusual to provoke a response from what was left of the Japanese air defences, had they been capable of such. Japanese radio even commented on a single B-29 bombing Tokyo, a "pumpkin" raider whose primary target was obscured by clouds, and switched to Tokyo without authorisation.