Bain Capital, a Boston-based private investment firm, said it has agreed to acquire a 50 percent stake in Jupiter Shop Channel Co. Ltd., a TV shopping channel in Japan, from Sumitomo Corp.

Bain paid about $1 billion in the deal, according to a person briefed on the matter.

Headquartered in Tokyo, the Jupiter Shop Channel broadcasts live 24 hours a day and sells such items as jewelry and fashion goods, beauty and cosmetic products, fitness products, home and interior products, home appliances, and food.

“We are pleased to enter this important partnership with Sumitomo Corp. and the company’s management team to accelerate the next phase of growth at Jupiter Shop Channel,” David Gross-Loh, a managing director at Bain Capital, said in a statement. “We believe the multi-channel strategy leveraging TV platforms, the Internet, and mobile technologies offers significant future growth potential in combination with ongoing efforts to further increase customer satisfaction by enhancing Shop Channel’s programming and services.”

Bain Capital has had an office in Tokyo since 2006; the office is currently staffed with about 30 people.