Sega Sues Memento Mori Developer for Patent Infringement, Seeking ¥1 Billion in Damages

Sega sues memento mori developer

Sega has taken legal action against Bank of Innovation (BOI), the developer behind the popular mobile game Memento Mori, alleging patent infringement. Filed in the Tokyo District Court, the lawsuit accuses BOI of violating five of Sega’s patents related to “gacha game” mechanics, a common feature in many mobile games. Sega is demanding a substantial sum of ¥1 billion (approximately $6.6 million) in damages and an injunction to halt the operations of Memento Mori.

The Patents in Dispute

At the heart of the lawsuit are five patents that Sega claims BOI violated. These patents, including JP 5930111 and JP 7411307, cover key gameplay mechanics related to gacha systems, which allow players to acquire in-game items of varying rarity through chance-based mechanics. Specifically, fusing items and gacha “pity” systems—features that ensure rare rewards after repeated failed attempts—are central to the dispute. Sega argues that these features in Memento Mori and BOI’s other game, Genjū Keiyaku Cryptract, infringe on their intellectual property.

Bank of Innovation’s Response

In response to the lawsuit, BOI has denied any infringement, stating that their games operate within the bounds of the law. The company revealed that they had attempted to resolve the dispute through negotiations with Sega, but the two parties failed to reach an agreement. Despite the ongoing legal battle, BOI has pledged to continue operating Memento Mori, while taking the necessary steps to ensure its availability to players.

Impact on the Industry

This lawsuit highlights a growing trend in the Japanese gaming industry, where larger companies like Sega and Nintendo are increasingly enforcing their patents against smaller studios. Legal battles over gacha mechanics have become more frequent, and the outcome of this case could set a precedent for future disputes. Industry analysts have noted the significant financial burden this lawsuit places on BOI, a relatively small company valued at approximately $150 million, making the ¥1 billion claim particularly challenging for them to handle.

As the case unfolds, the resolution will be closely watched by developers and publishers alike, potentially influencing how gacha mechanics are implemented in mobile games moving forward.