Some of the latest mobile phones in Japan come with motion sensors that let users detect motion or play action games like those on the Nintendo Wii console.
The D904i from NTT DoCoMo, Japan's top mobile carrier, contains a tiny motion sensor that detects shaking and tilting, company spokesman Nobuyuki Hatanaka said.
Instead of punching a keypad, users can move the handset like a tennis racket or fishing pole in easy-to-play games, similar to those on Nintendo Co.'s popular Wii.
In the "Tokyo Highway Battle" racing game, users twist the handset like a steering wheel to control driving. In "Skateboard Dash," the phone can be tilted to control the board's speed and direction.
Meanwhile, two new phones from Sharp Corp. and Matsushita Electric Industrial use their built-in cameras to detect motion. Users can control a hip-hop dancer by wagging a finger in front of the camera, for example, or throw punches in the air for a boxing match.
DoCoMo warns users not to go overboard with the handsets, however.
"If you swing or swerve too hard, it'll be hard to keep your eyes on the screen, and you might bother those around you," Hatanaka said. "We're talking about somewhat subtler motions."
Downloading games to play on the go is popular in Japan, where most mobile phone users are signed up for third-generation networks that offer fast data communication. Users download games onto their handsets to play for a set monthly fee.
The new phones are expected to hit Japanese stores in May. There are no current plans for overseas sales.