Popular Japanese video game Monster Strike raked in US$7.2 billion in five years and is the top-grossing mobile app of all time

Think Pokémon Go is a hit? Then you probably have not played Monster Strike. 

The five-year-old Japanese video game has raked in more than US$7.2 billion in gross revenue, making it the world’s highest earning mobile app of all time, according to data published this week by Sensor Tower.

The previous record holder, according to the US research firm, is another Japanese title called Puzzles & Dragons, which has grossed an estimated US$7 billion since its release in 2012. But unlike its head-to-head rival, Monster Strike does not even have an English version.

For some context, Pokémon Go grossed just over US$2 billion to date, and almost US$85 million in September, compared to US$112 million by Monster Strike during the same month, according to Sensor Tower.

So just what is so captivating about the game?

Monster Strike offers a cocktail of pool, pinball, and Pokémon-like game elements. In the game, players battle waves of monsters to collect, train and evolve them, with gameplay similar to flicking marbles around on a board. Up to four players can play simultaneously with each other online. The game is free to play, but offers in-game purchases of tools that help players continue a lost mission, expand the number of monsters they can own, and hatch stronger and rarer monsters, among other things.

Developed by Tokyo-based Mixi Inc, Monster Strike generates its revenue primarily from an ever growing home fan base. With 45 million downloads to date, its revenue rose 6 per cent year in the third quarter, according to Sensor Tower.

For now, Monster Strike remains a Japanese phenomenon. It pulled out of the US market last August, with local publisher Xflag saying in a statement that it is difficult to “sustain the game at a satisfactory level.”

In China, Monster Strike was published by Tencent for less than a year before its closure in October 2015. Last year, Mix relaunched the game in China by itself, but the response has been lukewarm in a market dominated by battle arena and survivor shooter genres such as Honour of Kings and PlayerUnknown's Battleground.