Run through

Japan’s leaders consistently displayed disinterest in the city bombing that was wrecking their cities. And while this may have been wrong when the bombing began in March of 1945, by the time Hiroshima was hit, they were certainly right to see city bombing as an unimportant sideshow, in terms of strategic impact. When Truman famously threatened to visit a “rain of ruin” on Japanese cities if Japan did not surrender, few people in the United States realized that there was very little left to destroy. By Aug. 7, when Truman’s threat was made, only 10 cities larger than 100,000 people remained that had not already been bombed. Once Nagasaki was attacked on Aug. 9, only nine cities were left. Four of those were on the northernmost island of Hokkaido, which was difficult to bomb because of the distance from Tinian Island where American planes were based. Kyoto, the ancient capital of Japan, had been removed from the target list by Secretary of War Henry Stimson because of its religious and symbolic importance. So despite the fearsome sound of Truman’s threat, after Nagasaki was bombed only four major cities remained which could readily have been hit with atomic weapons.

The thoroughness and extent of the U.S. Army Air Force’s campaign of city bombing can be gauged by the fact that they had run through so many of Japan’s cities that they were reduced to bombing “cities” of 30,000 people or fewer. In the modern world, 30,000 is no more than a large town.

What does "run through" mean?