Following an investigation, the Japanese Consumer Affairs Agency has issued a ban on "kompu gacha" style online social games.
Andriasang reports the CAA has ruled the kompu gacha system qualifies as card combination, a banned sales method.
As such, from July 1 companies fronting a kompu gacha system may face legal penalties. The CAA will release a full report today.
Earlier in the week, several social gaming publishers announced their decision to withdraw kompu gacha system, notable Mobage, Gree, Konami and Namco Bandai.
In kompu gacha games, players pay for a random game item, and have a small chance of collecting a whole set, which will return a rare reward. The CAA received a number of complaints of mounting bills before launching its inquiry.