Japan boasts some of the fastest and cheapest broadband services in the world, thanks to fierce competition waged by new entrants like Softbank Corp. against telecommunications behemoth NTT Corp.

While today ADSL (asymmetric digital subscriber line) is the dominant form of high-speed Internet access here, much faster fiber-optic services are seeing a rapid rise in subscribers.

Unlike Softbank's success in attracting more than 4 million users to its ADSL service, no one has yet captured a significant chunk of the fiber-optic service, called FTTH (fiber to the home), from NTT, which has a dominant market share.