While shipment figures aren't always great indicators of sales, 580,000 in one month compares reasonably to the 700,000 copies Dead or Alive 4 shipped worldwide in its first two months.
Tecmo also revealed a year-on-year improvement of 26.0% for operating income in the first half of its fiscal year, up to ¥897 million ($11.3 million). The company's revenue improved by 0.7% up to ¥13,724 million ($172.7 million).
Meanwhile, the game's third wave of downloadable outfits hits Japan today. Tecmo hasn't yet revealed when they'll be available here - revealed being very much the operating word.