While Apple may be struggling to break into the top three spots in China, the story in Japan is quite different. With dramatic improvement in sale of iPhone 4S in Japan, Apple has become the top smartphone seller in the country. According to Rethink Wireless, “This reflects a dramatic shift in consumer habits over the past couple of years, as consumers - accustomed to relying on advanced but proprietary devices commissioned by operators - have finally embraced open smartphones.”

Rethink-Wireless.com reporter Caroline Gabriel wrote, “Success of iPhone 4S finally ends consumers' love affair with homegrown brands and allows Apple to leapfrog Sharp and Fujitsu.”

As per this report, Apple has exploited this shift in consumer trend by forming a relationship with Japanese mobile communications company Softbank. Until last year, Softbank was exclusive distributor of the iPhone in Japan. However, according to the report, Apple has yet to ink a distribution deal with the market leader, NTT DoCoMo. With 60 million subscribers, NTT DoCoMo accounts for almost half of Japan's mobile user base. Meanwhile, the company has been granted permission to sell the iPad.

Data from research firm IDC shows that iPhone 4S accounted for nearly 26.6 percent of cell phone sales in Japan in the fourth quarter of 2011. Rethink-Wireless.com reported that this figure was well ahead of the local suppliers, which traditionally dominate the market because of their close alliances with the three main carriers, including NTT DoCoMo.

Gabriel wrote that the deals are more than normal distribution agreements. “The operators often co-design devices and co-fund R&D and marketing.”  Gabriel added, “that has left vendors like Sharp with products which are hard to sell abroad as they are tailored for Japan's unusually advanced mobile web user habits as well as its particular spectrum bands and user interfaces.”

Research firm IDC’s rankings indicate that Fujitsu is now the biggest handset supplier in Japan, overtaking long time leader Sharp. This rise is attributed to Fujitsu’s joint venture with Toshiba, which united the two electronics giants' mobile activities. However, the Rethink-Wireless.com report suggests that Toshiba is now exiting this deal and the sector. In Q411, this firm had 18.3 percent share, while Sharp had 15.7 percent.

Although, Apple took the top spot in 4Q11, the rankings for the full-year reveal a more common pattern for Japan. For the full year, Sharp leads with 20.1 percent share followed by Fujitsu-Toshiba with 18.8 percent and Apple on 14.2 percent.