The exchange student crafted automated characters (bots) that would thieve fellow players' goods so that they could be sold at auction. He faces hacking charges but cannot be charged with theft because laws do not cover virtual property.
The goods, taken from the game Lineage II, such as credits, weapons and magical items can be traded between players and are the subject of a lucrative online business. According to Japanese newspaper Mainichi the transactions in this case occurred online, within the game itself. Some people are said to earn a living from the trade.
Family man Julian Dibbell works full time as a virtual trader "selling castles in the air," he told the BBC.
Hacking is big news in the far east, with rumours of an online war waging between the Japanese and Chinese that started because Japanese history books removed details of past war crimes.
Japan is also embroiled in an online territorial dispute with South Korea.