Created: 9 April 2010 · Last edited: 16 October 2026

After a one-year pause, in May 2008, the Japanese operator Willcom announced a new portable device made by Sharp — the WS016SH, a.k.a. the Willcom D4.

The Willcom D4 slides open to reveal a full keyboard, but it does more than that — once open, the display can tilt upwards into an L-shaped position, making it very comfortable to view the screen while typing.

The screen can rotate, but not via a built-in rotation sensor, as in modern devices; instead, rotation is controlled by pressing a button on the edge of the device.

The Willcom D4 runs Windows Vista but can be downgraded to Windows XP. The initial version, released on 11 July 2008, came with Microsoft Office Personal 2007 with PowerPoint 2007 and a small 960 mAh battery as standard, providing only about 1.5 hours of operation. A larger-capacity 2,880 mAh battery was available as an option, extending operation to about 4.5 hours.

On 4 September 2008, the so-called Ver.L was released, with the large-capacity battery supplied as standard. This increased the Willcom D4's weight to 575 grams. Microsoft Office was no longer included with this version.

The WS016SH is powered by an Intel Atom 1.33 GHz processor (making it the first UMPC to feature an Intel Atom processor), has 1 GB of RAM (533 MHz DDR2) and offers 40 GB of HDD storage, plus an SDHC expansion slot. It boasts an impressive 5-inch touchscreen with a resolution of 1024 × 600 pixels, LED backlight and support for 262,144 colours.

Connectivity options include the PHS mobile network, Wi-Fi (802.11b/g), Bluetooth 2.0 + EDR and One-Seg digital TV.

The WILLCOM D4 can be paired with a rather unusual accessory: the WD4-BHGS, a tiny Bluetooth handset made by Group Sense. Designed to make phone calls more convenient on a device that is essentially a miniature Windows Vista PC, it looks like a small mobile phone, complete with a display and call controls. It can show caller information, store contacts and handle calls wirelessly, allowing users to talk without holding the considerably larger D4 to their ear. The handset comes with its own charging cradle and is a more phone-like alternative to the wired headset supplied with the computer. Despite its appearance, however, it isn't an independent mobile phone – it relies on the WILLCOM D4 for its calling functions.

The Willcom D4 measures 192 × 84 × 25.9 mm and weighs about 460 grams, which is remarkably little for a fully fledged UMPC.