Ever since June 2008 when Apple Inc.'s iPhone debuted in Japan and sparked a smartphone boom, Softbank Corp., Japan's third-biggest carrier in subscriber numbers, has enjoyed its status as the only carrier providing iPhone services in Japan.

But the announcement by Apple Inc. late Tuesday in the United States about the introduction of the latest model, the iPhone 4S, could be a major game-changer.

Apple said KDDI Corp., the second-biggest carrier, will also provide the iPhone under the au brand.