Yahoo Japan Corp. surprised the telecommunications market in March by announcing it would acquire eAccess Ltd., operator of mobile Internet service Emobile, and personal handyphone service Willcom Inc. to start a cellphone carrier in June.

The Web portal giant — part of the SoftBank group — said the new cellphone firm would be named Y!mobile and become the nation's first Internet carrier as well.

Yet the announcement has given rise to several questions, such as what kinds of services Yahoo Japan has up its sleeve, why it has to buy both eAccess and Willcom, both of which are in the SoftBank group, and whether Yahoo Japan and SoftBank Corp. will resort to fighting each other for subscribers in the future.