The first few years of smartphone gaming were, at least in Japan, not much more than a continuation of what had been happening with feature phones.
Puzzle & Dragons entered development in August of 2011, releasing first in Japan in February of 2012 with scattered releases in other regions over the next few years. Within mere days of its launch in Japan, it hit the number one spot in the top grossing apps chart on the Apple Store. With only a few brief lapses, it has held that spot for over four years as of this writing. Like Pokemon had done before it, Puzzle & Dragons changed the face of mainstream gaming in Japan. It represents a huge pivot towards mobile, both for developers and players, one that is largely still in effect today. As Dragon Quest had done for the JRPG sub-genre, Puzzle & Dragons set down the blueprint for what a social RPG should look like. It didn't take long for others to follow.
In a lot of ways, Puzzle & Dragons represents the culmination of everything we've been looking at. It's easy to pick up and play in short bursts and put down when necessary, like Final Fantasy Legend. Its collection aspects are obviously heavily influenced by Pokemon. Its open-ended, mission-based structure is a nod to Monster Hunter Portable. The puzzle-RPG hybrid idea was likely drawn from Puzzle Quest. The idea of having a friend's party leader in your group feels like it could have come from Dragon Quest 9. And like many of the most successful handheld RPGs before it, it feels perfectly designed both around its platform and its pay model. Indeed, if you strip away the free-to-play mechanics of Puzzle & Dragons, it loses something in the process.