A free mobile game about a traveling frog has become a hit in China, despite being available only in Japanese.

Called “Tabikaeru: Travel Frog,” the main protagonist of the game is a frog that goes on adventures around Japan. Players collect clovers that grow in the frog’s garden so they can buy supplies for the frog’s journeys.

In turn, the frog sends players souvenirs and snapshots from its travels. Users cannot control when the frog chooses to go on its adventures.

While news of the game’s appeal among mobile phone users on the mainland was first reported on by local media outlets last week, its popularity hasn’t diminished in any way since: “Travel Frog” on Monday was still ranked first on a list of the most downloaded games from Apple’s app store in China.

Behind the craze is Japanese game developer Hit-Point, which was previously best-known for creating the popular cat-collecting game “Neko Atsume.”

Even though it’s difficult to pinpoint what has driven interest among mainland users in “Travel Frog,” which is still only available in Japanese, local media outlets reported that mainland players said the game’s slow nature was part of its charm.

The game was popular as it “tap[ped] the trend among younger generations in China to search out ‘Zen-like’ activities,” China Daily said, adding that those users were taken with its “Buddha-style gameplay.”

But not everyone is thrilled about “Travel Frog.”

In a post on social media platform Weibo last week, the state-run People’s Daily opined that people should aim to enrich themselves and “avoid being a lonely frog-raising youth.”

As an indication of the popularity of the “Travel Frog,” Apple has already had to remove from its store an app that appeared to masquerade as the Chinese version of the original, the South China Morning Post reported.

That version of the game, which was created by a developer called Song Yang, charged users 30 yuan ($4.74) to download the game, the South China Morning Post said.

On Monday, another free-to-download app available on the app store claimed it offered strategies and guides in Chinese that players could adopt to improve gameplay.

While Hit-Point has not responded to inquiries about whether or not it intends to develop versions of the game in other languages, the company did put out an English update for “Neko Atsume” in 2015.