Now the two companies could set aside their rivalries to allow iPod users here to access Sony's roster of Japanese artists.
"We are negotiating with Apple over the download business and hope to expand our customer base to iPod users," said Yasuhi Ide, a spokesman for Sony Music Entertainment (Japan) Inc.
Last month Apple started its online music service in Japan, the world's second-biggest music market after the United States, to offer one million songs to iPod users.
It made an impressive start, hitting one million downloads within just four days, the fastest pace in the 20 countries where Apple's online music service is available.
With over 21 million users worldwide, the iPod is far more popular in Japan than Sony's Walkman Square. The Japanese group will launch a new digital Walkman dubbed the "Walkman Bean" next month as it takes aim at the iPod.
Japan's top-selling daily Yomiuri Shimbun on Monday quoted a music industry source as saying Sony's move was like "helping the enemy" but the spokesman said the company only aimed to reach out to more music fans.
"We simply want iPod users to listen to our music," Ide said, adding the deal could bring some 25,000 songs by the company's Japanese artists to iPod users.
The Yomiuri said the Apple-Sony music service could begin as early as this year but the spokesman declined to confirm the report, saying the two firms had yet to decide on details including a price per song.