The Act on Specified Commercial Transactions ("ASCT") and the Act on the Regulation of Transmission of Specified Electronic Mail ("Anti-Spam Act") regulate the sending of unsolicited electronic commercial communications.

Under the ASCT, which focuses on internet-order services, a seller is prohibited from sending email or fax advertisements to consumers unless they provide a prior request or consent (i.e. an opt-in requirement). The seller is also required to retain the records that show consumers' requests or consents to receive email or fax advertisements for 3 years for email advertisements and 1 year for fax advertisements after the last transmission date of an email or fax advertisement to the consumer.

If a seller has breached any of these obligations regarding email advertisements, such seller will be potentially subject to fine of up to JPY 1,000,000.

Under the Anti-Spam Act, which broadly covers commercial emails (e.g. an invitation email from a social network service), there are several regulations on sending email advertisements as follows:

• the sender must retain records evidencing there was a request or consent to receive emails at least for 1 month after the last date the seller sent an email to the recipient; 
• for-profit entities or individuals engaged in business sending any email to advertise their own or another’s business must obtain a request or consent to receive emails from intended recipients unless the recipient falls under certain exceptions (e.g. there is a continuous transaction relationship between a sender and a recipient) in the Anti-Spam Act; 
• an email is required to include a sender’s email address or a URL so that recipients can send opt-out notices to the sender; and 
• senders must not send emails to randomly generated email addresses (with the hope of hitting an actual email address) for the purpose of sending emails to a large number of recipients.

The relevant ministry may order a sender to improve the manner of email distribution if the sender violates the requirements noted above.  If the sender violates an order issued by the ministry (other than one related to the retention obligation), the sender is subject to imprisonment for up to 1 year or a fine of up to JPY 1,000,000.  In addition, the entity will be subject to fine of up to JPY 30,000,000 if an officer or an employee of the entity commits any violation mentioned above.  If the sender violates an order issued by the minister with respect to the retention obligation, the sender will be potentially subject to fine of up to JPY 1,000,000. In addition, the entity will be subject to fine of up to JPY 1,000,000 if an officer or an employee of the entity commits the violation mentioned above.