TOKYO – Rupert Murdoch’s News Corp. and Masayoshi Son’s Softbank Corp. on Tuesday launched Japan Sky Broadcasting (JSkyB).The joint venture firm will begin broadcasting 12 channels in April and plans to eventually offer 150 channels. The launch of JSkyB sets the stage for a battle for viewers between the Murdoch alliance and rivals including a digital satellite broadcaster owned by Hughes Electronics Corp., part of General Motors Corp. Another prospective rival is Hughes Corp.’s DirecTV, which plans a 100-channel service in Japan in fall 1997. “News Corp.’s expertise in worldwide programming and satellite operations combined with Softbank’s expertise in retail electronics distribution and digital interactive and data services will ensure JSkyB’s success,” Murdoch said at a press conference. JSkyB was capitalized at 20 billion yen ($177 million), 80% from Softbank and 20% from News Corp. Son said that while Softbank was laying out the majority of the capital funds, the two companies are “equal partners.” Murdoch will be founding chairman of JSkyB, while Son will be founding president. Last month, JSkyB reached agreement with the Japanese digital multichannel platform PerfecTV to offer channels to each other’s subscribers. The two companies are negotiating using common receivers for their services. Subscribers to JSkyB and PerfecTV will have access to 360 channels once the two satellite broadcast providers begin offering all their planned channels by 1998. The two companies said they expect their subscribers to reach a combined 10 million in 2000. The Kyodo News Service in Tokyo quoted industry sources as saying Murdoch had asked Sony to buy a stake in JSkyB and that the investment was one of a number of options being considered by Sony. Company executives weren’t immediately available to comment on the report.