When Microsoft first released Windows 7 in Japan, they shocked the otaku community by including the first ever official OS-tan, Nanami Madobe. Since then, Nanami Madobe fanart has been popping up on the internet every once in a while, but did you know that Microsoft has since released six more OS-tans?

On December 18, 2009 Microsoft began a month-long Bing promotion in Japan where users would be given a present for using the Bing search engine a certain number of times. That present turned out to be 5 more OS-tan themes that you can install on Windows 7. The new OS-tans (pictured below) from the left working clockwise are: Nanako, Nanae, Nanao, Nanami, and Nana.

In case you’re wondering, the word “nana” means seven in Japanese, but also makes up the beginning of several names. They all have either the Windows logo, “bing”, or “W7” somewhere on their body, but each of them represents a character archetype commonly seen in anime. Nanako is the childhood friend, Nanae is the office lady, Nanao is the tomboy, Nanami is the robot/android, and Nana is the little sister.

Those of you familiar with anime character types may be asking where the eyecandy girl is. Well, on September 27 Microsoft unveiled Hikaru Aizawa, the OS-tan for Silverlight. A busty blonde girl, Hikaru fits the eyecandy role perfectly.

She also seems to be more fun than the other OS-tans, even dressing up in a new costume for Halloween this year.

With Microsoft churning out all of these OS-tans, you have to wonder how many more are going to come out. Personally, I’d like to see Microsoft make a tsundere-type OS-tan, and if they do, I wonder what they’ll have it represent.

So I’m sure by now everyone is already aware of the upcoming release of Windows 7 and all the new and improved features it comes with, but you might not have heard of Nanami Madobe. According to Akiba PC, the Japanese version of Windows 7 Ultimate will be getting an OS-tan named Nanami Madobe who will be voiced by popular singer Nana Mizuki. So what is an OS-tan you ask? simple, it’s basically a mascot character drawn anime-style that represents an operating system (more details here).

The problem with Nanami though, is that she was actually created by Microsoft, unlike the other OS-tans which were all fan-made. One could argue that Nanami isn’t a real OS-tan because she wasn’t created by fans. It would be interesting to see if the OS-tan community will accept her the way she is, make some slight modifications, or create a new character entirely. Personally, I think she fits in pretty well with the other OS-tans:

Anyone care to guess who’s who?