It was February 2012 when GungHo Online (#9 in our Top 50 Developers of 2016 list) launched Puzzle & Dragons: a game that surprised it as much as the rest of the world by being the first mobile game to $1 billion in revenue (in 2013).
And, despite a declining user base in its core Japanese market, it's still generating over $1 billion annually.
Indeed, as the graph below demonstrates, it's a regular at the top of the Japanese top grossing chart for iPhone, although competition from the likes of Mixi's Monster Strike means its stays at the top of the chart are becoming less frequent.
Its position on Google Play (Japan is pretty much split 50:50 in terms of App Store and Google Play revenue) is stronger, although that's partly because of the way the Google Play chart position is calculated.
Indeed, given it's generated 41 million downloads in Japan - effectively saturating the market - over the past 12 months, GungHo has been heavily pushing the game outside of Japan, especially in the US and other Asian markets.
Surprisingly, though, the game is only available in 33 countries compared to the 150-odd countries a typical global launch would target.
Big in America
In North America - where it's generated over 9 million downloads thanks to strong marketing include TV ads - the game has been a strong top 100 performer on Google Play in the US and Canada.
On iPhone, its chart progress has been more spiky, however, which is likely a byproduct of the game's strong cadence of events. Revenue rises with events and then falls inbetween times.
Looking at other Asia markets, the localised version of Puzzle & Dragons has also done well in the competitive South Korea market (2 million downloads in total), although it's now spiking into the iPhone top grossing top 100 rather than maintaining a steady position.
The position is broadly similar on Google Play; note - Korea is a majority Android market in terms of game revenue.
Similarly, in Taiwan and Hong Kong on Google Play (2 million downloads between them), Puzzle & Dragons has now fallen outside of the top 100 grossing for the first time in Taiwan since a localised version was released in 2014.
In Hong Kong, its performance is stronger. Indeed, it's currently back up into the top 20.
Given the strength of Android in these markets, there's not been a simplified Chinese version of the game released for iPhone.
So what's next for Puzzle & Dragons?
In Japan, the game is certainly into a state of managed decline.
That's not to say sales will fall off a clift, but given Japan provides the vast majority of revenues, it's very hard to see Puzzle & Dragons generating $1 billion in 2016.
The two unknowns are whether GungHo Online will leverage its US experience and market big in Europe, and what's happened to the official Chinese launch?
A deal was signed with Tencent in late 2014, but there's not been any news since, with the one uncertainty in this situation being how many Chinese are already playing the Hong Kong version.