Japanese legal experts have said an antitrust case related to a local restaurant website could change how large internet platforms such as Google, Facebook and Amazon operate in the country, forcing them to reveal the inner workings of their secret algorithms.

Last month, a Tokyo court ruled in favour of Hanryumura, a Korean-style BBQ restaurant chain operator in an antitrust case brought against Kakaku.com, operator of Tabelog, Japan’s largest restaurant review platform.

Hanryumura successfully argued that Kakaku.com had altered the way user scores were tallied in ways that hurt sales at its restaurant outlets. While Kakaku.com has been ordered to pay Hanryumura ￥38.4mn ($284,000) in damages for “abuse of superior bargaining position”, the internet company has appealed against the decision.