Why is it called Windows 10 not Windows 9?

One of the most surprising aspects of yesterday’s Microsoft event was the name of its new operating system: Windows 10. Not Windows 8.2  or Windows 9… but Windows 10. When asked about Windows 10′s name, Windows chief Terry Myerson and Joe Belfiore avoided a direct answer, instead joking about how “seven ate nine” and then lamely saying how the “breadth of the product family” justifies the grandiose name. So, really, why did Microsoft call it Windows 10 instead of Windows 9?
Updated 6:39am October 2: I’ve added two other alternative (conspiracy?) theories on why it might be called Windows 10 rather than Windows 9. I would take these theories with a large pinch of salt — but I’ve included them because they’re just about feasible enough that they might actually be real.

 

Microsoft officially unveiled Windows 10 this morning, and the company is planning to distribute a Technical Preview of the new operating system tomorrow. At Microsoft's event today there were a number of machines running the Windows 10 Technical Preview, and I got an opportunity to briefly explore the new OS. While Microsoft pushed hard with touch on Windows 8, Windows 10 is the complete opposite. If you mouse into the corners to find the tricky Charms Bar they no longer trigger and frustrate. Instead, you're greeted with the familiar Windows desktop and Start Menu from the moment you use Windows 10. It's Windows 7 right now and very early in its development, but it has some interesting improvements waiting inside.

The Start Menu is the most obvious addition. Just like in Windows 7 and other versions before it, the Start Menu largely acts in the same way. Microsoft has done a u-turn here, but it's also considered the way it can modernize its Start Menu and it appears to have paid off. It's customizable enough that you can resize it, pin traditional and modern apps, or simply have it match the color of your desktop wallpaper. These hints of Windows 8 shine through directly in the Windows 10 Start Menu, and although the overall interface feels like the Windows desktop, the Start Menu feels truly new and yet familiar at the same time.

Some alternative theories for skipping Windows 9

After publishing this story, some other possible reasons for Microsoft skipping Windows 9 came to light. I am dubious about both of these alternate theories, but they have just enough truthiness in them that I’ll share them with you.
First, an ExtremeTech reader called Benny emailed me to say that the number 9 is considered unlucky in Japan. Microsoft has a big enough presence in Japan that it may have skipped Windows 9 to avoid any weirdness or ill will. Benny says that Trend Mi
cro — a Japanese company — did the same thing a few years ago when it skipped version 9 of its antivirus software.