Wal-Mart Stores Inc. WMT -0.28% is expanding in Japan for the first time since 2008, sensing an opening as increases in the ranks of the working poor and pensioners on fixed incomes propel a trend toward thrift there.

The retailer is planning 22 new stores in Japan in the next two years, as well as scouting for acquisitions to enlarge its 368-store presence in the world's second-largest consumer market, where it got off to a rocky start about 10 years ago.

"I expect single-person households will continue to grow and people will have less money and all of that plays to our strengths," said Steve Dacus, president and chief executive of Seiyu and Walmart Japan Holdings.

Japan hasn't been an easy country for the Bentonville, Ark., retailer, which arrived a decade ago through a partnership with Seiyu Ltd., a national grocery chain that wasn't thriving. The market is highly fragmented, and finicky Japanese shoppers, who traditionally equated discounts with poor quality, were slow to embrace the retailer's modus operandi of low prices and broad merchandise selection.

Wal-Mart acquired Seiyu in full four years ago, and continues to use that name, rather than operate under the Wal-Mart banner. Its fortunes began turning several years ago as demographic and economic shifts began altering Japanese consumer spending habits.