During remarks at a developers conference in Japan on May 23, Microsoft CEO Steve Ballmer referred to the next version of Windows as “Windows 8.” He also said the next generation of Windows systems will be out next year.

To those not following Microsoft’s Windows saga closely, this may seem like a “so what” moment. But Microsoft execs have been studiously avoiding any references to the timing or naming of the next version of Windows to try to keep the specifics of the product as quiet as possible. Microsoft’s top brass has been avoiding calling the next version of Windows “Windows 8″ publicly, preferring instead to call it “Windows Next.” (Internally, a number of  Microsoft job postings and leaked slides have referenced “Windows 8,” however.”

Here’s what Ballmer said today in Tokyo about Windows 8, according to Microsoft’s own transcript:

“We’re obviously hard at work on the next version of Windows. Windows 7 PCs will sell over 350 million units this year. We’ve done a lot in Windows 7 to improve customer satisfaction. We have a brand new user interface. We’ve added touch, and ink, and speech. And yet, as we look forward to the next generation of Windows systems, which will come out next year, there’s a whole lot more coming. As we progress through the year, you ought to expect to hear a lot about Windows 8. Windows 8 slates, tablets, PCs, a variety of different form factors.”

Parsing Ballmer’s words further, it’s interesting he called out Windows 8 slates and tablets as two separate form factors. Last year, Microsoft was pushing Windows Embedded Compact as its slate operating system, designed for devices that were more about consumption than creation….

It’s also interesting that Ballmer did not say specifically that “the next generation of Windows systems” due out next year were Windows 8 systems. (There’s been some speculation that Microsoft might deliver ARM-based tablets separately from Windows 8 laptops, PCs and notebooks — with some company watchers predicting that Win8 tablets would ship before the other SKUs, and others predicting they’d ship afterwards. I’ve heard from my contacts that Microsoft is planning to deliver all Windows 8 SKUs simultaneously, however.)

The head of Windows, President Steven Sinofsky, is slated to speak next week at the AllThingsD conference, where many are expecting him to show off an internal build of Windows 8 (whether or not he actually refers to it using the Windows 8 codename).

Microsoft is expected to provide testers with a first tech preview or beta of Windows 8 in mid-September during the company’s developer conference in Anaheim, Calif. The rumored release-to-manufacturing date of Windows 8 is mid-2012, with holiday 2012 retail availability targeted.

Update: OK, believe it or not, the “official” response is Ballmer’s statement isn’t what it seems to be… Sent from a Microsoft spokesman earlier tonight:

““It appears there was a misstatement. We are eagerly awaiting the next generation of Windows 7 hardware that will be available in the coming fiscal year.  To date, we have yet to formally announce any timing or naming for the next version of Windows.”

And, as usual, there are many ways to interpret these remarks. Is the next-generation Windows release nothing but Windows 7 with new paint? Windows 8 not the final name for the next version of Windows? (The final name possibly being something other than Windows 8 is something that I’ve heard from my tipsters…) You be the judge….