Atsushi often came to school late, fell asleep during classes and his academic performance was deteriorating. He told the teacher he was spending most nights playing online games until the early hours.

When the teacher said, "So you think you're going to be able to make a living through computer games?" Atsushi flashed him an irritated look and replied: "I'm already making money. About 100,000 yen (US$1,080) a month."

The teacher concealed his surprise and retorted: "That's hardly enough." But Atsu-shi smiled and said, "I could earn more if I wanted to."

Nine months later, Atsushi was arrested by the Metropolitan Police Department on suspicion of electronic fraud. Charges against him included an allegation that he defrauded an online game-operating company of a total of 36 million yen ($388,959) worth of virtual currency from .

Virtual currency is used in an online game. With the virtual money, game players can buy weapons, clothing and other items in the game.

Players can earn the virtual money by performing tasks on the game site or defeating enemy characters. Players also can buy the virtual currency with real money and exchange the currency for real cash at "real money trading" Web sites, but the exchange rate is often only half the value of the virtual money.

Atsushi first used a personal computer in his second year at primary school and began playing online games in his fifth year of primary school.

Upon returning home from school, he would stay in his room and continue playing online games until 2am or even later. He also read numerous books about hacking and other computer techniques.

Atsushi told the police he believed that if he could find a loophole in the computer programme, it would then be easy to steal virtual currency used in the online game.

He was quoted as saying that in the spring of his second year of high school, he repeatedly hacked his way into the company's computer server by finding out the ID numbers of company employees and their passwords.

In October that year, Atsushi apparently succeeded in hacking into the company's system for managing the virtual currency for the game. Starting with an amount of less than 10,000 yen ($108), he was able to increase it to 36 million yen by manipulating computer data over a period of three days, the boy told the police.

Using Web sites that allow game players to exchange virtual currencies for shopping coupons and shopping points at online stores, Atsushi changed the virtual currency into real money and used it to buy goods from online stores.

Atsushi spent 27 million yen ($291,635) worth of the virtual currency of which police believe he spent 7 million yen ($75,609) in the real world.

A pair of sneakers priced 40,000 yen ($432), portable game machines and luxury foods such as crab were delivered to his home.

Of the amount he is believed to have gained through the fraud, Atsushi allegedly spent 10 million yen ($108,023) worth to buy his own game items. The most expensive item he bought on the game site was a dress for a princess priced at 100,000 yen ($1,080).

He allegedly spent the remaining 10 million yen ($108,035) on game items that he later gave away to other players of the game. He placed items at various locations in the virtual world of the game and announced to other players that the items were available there free of charge.

The police quoted Atsushi as saying: "Everybody would dash to the spots where I left the items. That was fun to see."

At school, Atsushi was a low-profile student without close friends. But among fans of online games, he was treated with respect as "the wizard of password stealing" or even "god".

The teacher said he felt anxious about Atsushi and wondered why he could not content himself with satisfying his pride in the world of online games alone.

Atsushi's punishment included being put under observation. But the police said he told investigators: "I'm going to play games again. Game companies with loose security are the ones at fault."

The computer system loophole that Atsushi took advantage of has since been addressed by the company.

But computer experts said that similar crimes aimed at stealing virtual currency still occur.

'More cash' from child porn

In May, a 19-year-old youth was arrested by the Kanagawa prefectural police on suspicion of posting pornographic images on the Internet.

He, too, was motivated by money. He apparently began operating a cell phone Internet site with obscene images when he was a third-year middle schooler. As the number of hits did not increase as he expected, he decided to specialise in child porn data when he was a third-year high school student.

The police quoted him as saying, "I believed (images of) little kids would bring in more cash."

His child porn site was accessed 600,000 times until he was arrested and the site closed. At one point he was earning up to 30,000 yen ($324) a month through advertising fees from his site.

He told the investigators that he operated the site only to earn money for recreation. The investigators said he looked a very ordinary boy. But the investigators added that they still felt the boy's facial expression when asked the following question was unusual: "Didn't you imagine how the girls whose pictures were shown on the site felt?"

The youth looked puzzled as if it had never occurred to him to even think about this.