Sony has named the day it will launch its assault on the portable gaming sector. The company will put its PlayStation Portable on sale in Japan on December 12.

The PSP, which the company has previously called its "Walkman of the 21st Century", promises to pack the power of a PlayStation 2 into a portable handheld device that will be priced at ¥19,800 (just over £100). That's slightly cheaper than many people had been guessing and about the same price as the PlayStation 2 console.

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Sony has yet to announce a launch date for the PSP outside of Japan. However, the company has said it intends to put it on sale in North America and Europe before the end of its current financial year, which finishes on March 31, 2005.

The face of the PSP is dominated by a 4.3-inch wide-screen LCD that offers 480-x-272 pixel resolution. It has a brightness of 200 candela per square meter, which is about the same as that of an average desktop PC monitor, although when using battery power this will be limited to 180 candela per square meter, the company said.

The PSP also features built-in support for wireless networking, which will allow users to connect to the Internet through an access point for online gaming and also to download new games. Through it, users can also create an ad-hoc network of up to 16 PSP terminals for online entertainment, Sony said. Other networking support includes a USB 2.0 port, MemoryStick Pro Duo slot and IrDA port.

SCEI measured battery life at about four hours with the display at maximum brightness and five hours at half brightness, the company said. In both cases, the volume was set half way, headphones were in use and the wireless LAN was switched off.

This is roughly double the two hours battery life quoted by company representatives at September's Tokyo Game Show. A Sony spokesman said those figures were likely for when the PSP was being used in movie mode rather than game mode.

The PSP device measures 170-x-23-x-74mm and weighs 280g.

By the end of this year there should be 21 games available for the PSP from Sony and third-party suppliers, Sony said. It named the games but did not specify their prices or launch dates.

They include Lumines, The Legend of Heroes Gagharv Trilogy White Witch, Vampire Chronicle: The Chaos Tower, Kollon, Need for Speed Underground Rivals, Tiger Woods PGA Tour, Armored Core Formula Front, Rengoku: The Tower of Purgatory and Dynasty Warriors.

Games will be supplied on a new optical disc-based media format called UMD, or Universal Media Disc. UMD discs measure 60mm in diameter and are encased in cartridges. Each 10g disc can hold up to 1.8GB of data.

The PSP will support versions of UMD discs for games, audio content and video content. UMDs featuring mixed game, audio and video content are expected on the market during the second quarter of 2005, Sony said.