By all accounts, it appears as if the launch of Apple's iTunes Music Store in Japan has been a success. Apple on Sunday announced that the music store had sold one million tracks in just four days - the best start for any of its 20 international music stores.

In comparison, it took the United States version of the store a full week to hit one million downloads.

"iTunes has become Japan's number one online music store in just four days," Steve Jobs, Apple’s CEO said in a statement Sunday. "iTunes has sold twice as many songs in just four days as all the other online music services in Japan sell in one month."

Analysts had publicly doubted that a music store that focuses on music downloads to a user's computer could succeed in the country due to the intricacies of the market. Japanese analysts said that there is no market for downloading music to a PC - only mobile phones.

Currently, such a feature is not supported. However, the response to iTunes indicates that there was indeed a market for PC downloads of music, but competing services were not compelling enough for consumers.

One possible reason might be price. iTunes songs are priced at either 150 yen ($1.35) or 200 yen ($1.80); competing services charge about twice as much. Apple has already passed rival Sony, which sees about 450,000 downloads in Japan per month.

But there is still work to be done, according to Apple executives. Sony's music label has still not signed on to list its catalog on iTunes, which includes some extremely popular Japanese artists. Apple would not comment on the status of talks, but did express optimism that the label would eventually join.

According to Apple, with the addition of Japan, the company now reaches about 85 percent of the global music market.