The PlayStation 4 selling 10 million consoles in nine months is more than what the company hoped for, and sales at that level defy “conventional thinking.” That’s according to PlayStation worldwide studios president Shuhei Yoshida, who tells Eurogamer that this figure could have been even higher if Sony was better able to meet supply demands.

“The 10 million sell-through in the first nine months is well beyond what we had hoped for,” Yoshida said. “As you know, we have struggled to keep up with demand of PS4 for so many months. It was hard to find and purchase PS4. Now we are able to supply units so in every territory I believe you can find PS4. So we just managed to catch up with demand. It’s just beyond our imagination. We are so happy.”

“Lots of people thought the dedicated game hardware might not be needed going forward, but still lots of people are very excited” — Shuhei Yoshida

Though Yoshida is thrilled about the console’s current sales pace, he pointed out that he is also “a bit nervous” because he says Sony does not completely understand how the PS4 was able to sell so well so quickly. “You need to understand why your products are selling well so you can plan for the future, right? It defied the conventional thinking,” he said. “Lots of people thought the dedicated game hardware might not be needed going forward, but still lots of people are very excited. When you see the new games coming out and being announced this E3 and Gamescom, I think there’s a good enough reason for a gamer to believe this is something worth investing in.”

Potentially explaining the PS4’s rapid sales is that gamers who were not historically PlayStation fans bought the console. “Some of the early data was amazing in terms of the number of people who didn’t used to own PS3 have already purchased PS4,” he said. “So we are getting lots of new customers coming into PlayStation. And some people never purchased any last-gen hardware: PS3, or Xbox 360 or Nintendo Wii.”

In an interview with Kotaku in June, Sony’s John Koller said that 31 percent of PS4 owners are new to the PlayStation ecosystem.

Also in Eurogamer’s interview, Yoshida said Sony needs to do more to understand who its customers are and what they want.

“As soon as we see a great sales number, our instinct tells us we should be concerned about future sales, right? Are we exhausting all the core gamers? If we sell this number of units, there are no more consumers we can sell to,” Yoshida said. “That’s a really terrifying prospect. So we want to understand who are these consumers who we do not necessarily consider core gamers, who are purchasing PS4 and why they are doing it and what they are doing with PS4, so we can create a bit more of a positive future, rather than saying, ‘Wow, we have sold to every single core gamer.’ So that’s what we are doing.”

Finally, Yoshida pointed out that Sony is always looking to add new features to the PS4 and introduce network services like PlayStation Now as a means to grow the brand overall. “So we hope we can continue this momentum and reach a wider audience than we were able to do on PS3,” he said. The PS3 has sold north of 80 million units worldwide.