The operator of the Mercari smartphone shopping service says it will tighten seller identification after a series of problems on items put up for sale.
The Mercari buy-and-sell app has become widely popular in Japan because of its convenience.
But items on sale have included shoplifted books and an upscale bicycle that was stolen. This month, 2 people were arrested for offering 120 baseballs stolen from a high school clubroom. They offered at least 2,000 balls on various sites.
In May, a receipt was offered for a price lower than the amount for which it was issued. And last month, a junior high school student was referred to welfare authorities for trying to sell information on how to download a computer virus.
Japan's National Police Agency says the law on trade of used items mandates confirmation of seller identity to prevent cashing of shoplifted goods.
But because the law does not apply to Mercari, the police had repeatedly asked its operator to identify people putting items up for sale.
The company decided to oblige first-time sellers to input their name, address and birthday. In addition, sellers will not be able to withdraw money paid unless their name matches that on their bank account. The company conveyed these measures to the police.
Mercari plans to put these new measures into effect by the end of this year. It is also considering a system to compensate victims in cases where police have confirmed items on offer were stolen.