In a 2005 bid to boost sales in its largest international market, Starbucks Corp. expanded its business in Japan, beyond cafés and into convenience stores, with a line of chilled coffee in plastic cups. The move gives the Seattle-based company a chance to grab a chunk of Japan’s $10 billion market for coffee sold in cans, bottles, or vending machines rather than made-to-order at cafés. It is a lucrative but fiercely competitive sector, but Starbucks, which has become a household name since opening its first Japanese store, is betting on the power of its brand to propel sales of the new drinks.