Manufactured by Sharp, sold by Willcom and able to operate Windows Vista Home Premium, the Willcom-Sharp D4 will be the first sub-notebook to run on an Intel Atom processor when it goes on sale in Japan in June.

Measuring 8.4cm wide by 19.2cm long and 2.6cm thick, the D4 weighs in at just 470 grams. Although too large for all but the biggest cargo-pant pockets, it’s still small enough to be easily stowed in a backpack, a shoulder-bag, or even, God forbid, a man-bag.

Despite its diminutive appearance, the D4 actually packs quite a punch, with the 1.33GHz Intel Atom processor complimented by 1GB of RAM and 40GB of 1.8-inch flash memory. Whichever way you look at it, that’s a pretty impressive spec for something this small.

Touchscreen

The 5-inch touchscreen is capable of displaying at 1024 x 600, although there’s also a 64-key Qwerty keyboard for data input. Oh, and a 2MP camera, a built-in TV tuner, full multimedia capability and a microSD slot.

Running on the Windows Vista Home Premium platform, the D4 will be supplied with Microsoft Office 2007 and PowerPoint pre-loaded.

Why, there’s even the option to attach an optional Bluetooth handset, just in case you, like, actually wanted to use it as a phone.

Only in Japan

While 802.11b/g Wi-Fi and Bluetooth 2.0 are both catered for, the initial batch of Willcomm D4 devices are designed to work uniquely over the (2G) Personal Handy-phone System (PHS) cellular network operated by Willcom throughout Japan.

Willcomm will no doubt be hoping that undecided customers will be seduced by the flat-rate unlimited mobile data deal it’ll offer new customers, rather like O2’s iPhone tempter. Rather like O2 though, it won’t be possible to have one without the other.

The total cost to those Japanese punters hoping to get their mitts on a D4 will be approximately £200, or £500 including monthly charges for the minimum two-year contract. There's no word on whether the D4 will be making an appearance outside of Japan yet, but we certainly hope so.