The only way a new game can truly be deemed a success is if it has at least two sequels — at least this is what Yosuke Matsuda, the CEO of Square Enix believes. Matsuda refers to this belief as the "Law of Thirds," in detail during an interview with Famitsu.
“Cultivating a new IP is very important,” Matsuda told Weekly Famitsu. “I believe that it is very difficult to immediately build up a big IP. Looking retrospectively at the gaming industry, many games take off or get their big break at their third title. There are cases where the opposite is true of course.”
One of these cases must be the Kingdom Hearts series, years after the game's release we are finally seeing the third installment and the only reason it has made it this far is because of the success procured by the initial game.
“You need at least three games before you can tell whether an IP is going to be really successful or not. If the third title is successful then all is well,” he added.
We will see this belief in action firsthand with Square Enix's new RPG, Project Setsuna. Not much is known about the game, but whether or not it is successful will be seen years from now if the game has a third addition to the (possible) series.