Prime Minister Shinzo Abe, who entered office at the end of 2012, has made reviving the economy a top priority. His plan for doing so, known as “Abenomics,” included fiscal and monetary stimulus combined with a promise of big structural reforms that would draw more women into the work force and get corporations to spend more on higher wages and new investments. His policies produced impressive results early on but have lost much of their oomph in recent months — partly because the government raised tax rates prematurely and partly because the promised structural reforms have not gone far enough.