Elementary and middle school kids in Japan are going wild over a cartoon called Yu-Gi-Oh!, which is serialized in a comic book magazine for boys. It's the story of an ordinary high-school boy named Yugi Muto who loves games. Yugi acquires a special power that turns him into a completely different, powerful persona, and in this form he defeats the bad guys by beating them in card games. Based on this series a GameBoy software, Yu-Gi-Oh! Duel Monsters, has been made. It's a game in which you fight the wizards and other rivals that appear before you using cards that give the player special powers and characteristics. The software went on sale in December 1998, and it sold an amazing 1 million copies within the first week. Here's how to play the game. You choose five cards from the set in your hands and lay them out with the face down. Then, you and your opponent--either another person or the computer--both turn over one card at a time. There are 350 kinds of cards, and by using the various offensive powers, defensive powers, and other characteristics of your cards skillfully, you can take away the opponent's life points. The player whose life points go all the way down to zero first loses the game. If it's just a match between two monsters, the winner would simply be the one with the stronger offensive or defensive power. But by using a "field" card, you can pick a setting for the battle--such as the sea or prairie--that is favorable for your monster. The players' strategies, as well as chance circumstances, can sometimes lead to dramatic situations, making it an exciting game. Using GameBoy's communication feature, you can connect two machines and play against a friend or trade cards. The more you play, the higher the chances of your coming across unusual and valuable cards, so there is also the fun of collecting all of the cards. In July 1999 another Yu-Gi-Oh! software for GameBoy machines went on sale. This has also sold very well--1 million copies in less than a week. There are also game cards that are made just like the ones that the cartoon characters use in the series, and many kids are into collecting them. In August 1999 a tournament was held at Tokyo Dome, where participants fought against each other with the new GameBoy software. The event's sponsor had also planned to sell limited-edition game-card packages, each containing five cards. But when some 50,000 fans gathered from across Japan--much more than expected--and about 10,000 of them couldn't even get inside the stadium, the sponsor canceled the sale of these cards as well as the final round of the tournament out of fear that accidents may occur. A similar situation arose at the Tokyo Big Sight convention center in December, when an event for the comic book magazine carrying the Yu-Gi-Oh! serial was held. A huge crowd of Yu-Gi-Oh! fans showed up, many of them arriving early in the morning in hopes of buying limited-edition goods. Entry into the building was cut off at noon, however, so only 20,000 of the 60,000 visitors could actually get in. Also in December 1999 a new pack of game cards for beginners went on sale. The Yu-Gi-Oh! fever looks set to continue for some time to come. Photo: The newest Yu-Gi-Oh! game pack (box at upper left) contains 102 cards as well as two sheets to use as game boards and a book of rules.