Concerned about the relative failure of the B-29 offensive to deal any crippling blows to Japan, General LeMay issued a new directive on 19 February. General LeMay had analyzed the structure of the Japanese economy, which depended heavily on cottage industries housed in cities close to major industrial areas. By destroying these feeder industries, the flow of vital components to the central plants could be slowed, disorganizing production of weapons vital to Japan. He decided to do this by using incendiary bombs rather than purely high-explosive bombs, which would, it was hoped, cause general conflagrations in large cities like Tokyo or Nagoya, spreading to some of the priority targets.