I'm not going into the merits of Ahonen's blog, and I admit that I do know little about the Japanese market. One thing I know is that they use a particular definition to describe "smart-phones" as opposed to "advanced function mobile phones".

The smart-phone category is comprised by their definition as "mobile devices running iOs, Android, MS Windows Phone, RIM's OS, and Symbian S60" (which is not offered in Japan). As are a few others (Bada, Maemo, WebOS). So, these are mainly imports (they start to release Japanese Android based phones in relevant numbers now).

Advanced function phones are mainly "Made in Japan" and not counted as smartphones.

I am not clear in which functions "advanced function phones" differ from smart phones, as all functions available on smart phones are seemingly present in these advanced function phones. Some functions that have been used in Japan for years are not currently present in the U.S. (emoney, virtual wallet) or have been introduced in Japan years earlier than to the rest of the world.

Understanding how smart phones are defined it is no wonder that iOs and Android make up more than 90% of the Japanese smart phone market.

Unit wise there were about 5 Million Android devices and more than 3 Million IOS devices sold in Japan in the latest fiscal year (12 months ending 3/31/2011), on average a little more than 2 million smart phones per quarter. That does not sound that much for a highly industrialized country like Japan with a population a little less than 130 million. There must be a huge number of advanced function phones be sold.

I'd appreciate if someone more knowledgeable can explain the distinction between smart phone and advanced function phone in Japan, or has numbers showing units sold of advanced function phones.