A Keitai is a Tamagotchi only released in Japan. It was released around the same time the Version Two was released. The Keitai was much like the V2, but came with loads of new features. The most outstanding feature was that the Keitai could connect to Japanese mobile phones. Unfortunatly these could not connect to mobiles outside Japan.
The Keitai also came with passwords, new things to do when connecting and it looked slightly different to ther Tamagotchis. They looked like a V3.