TOKYO — Rupert Murdoch has created a joint venture company with Japan’s hottest music producer, Tesuya Komuro, in order to make an aggressive push into the global music market, sources close to the deal said Wednesday in Tokyo.The accord between the two was reached after months of negotiations that involved the Aussie-born media mogul’s eldest son, Lachlan, who serves as a top executive of News Corp. in Australia, and the Japanese producer. No financial details were yet available. Murdoch has become increasingly active in Japan lately: News Corp recently took a substantial minority stake in broadcaster TV Asahi and is now planning the launch of a digital platform in that country with local partners next year. It is believed that this latest joint venture will involve Murdoch’s pan-Asian satcaster Star TV as a key distribution mechanism for Komuro’s music throughout the region. A News Corp. exec in Tokyo, Misako Matsumoto, said that a press conference announcing the deal with Komuro would take place Friday in Los Angeles.