New Super Mario Bros 2 shows an obsession with gold coins we haven't seen the likes of since Yukon Cornelius in the old Rudolph TV special. So what inspired the developers to make the sweet clink-clink of coins the central point of the game? Apparently it began from a power-up in Super Mario 3D Land, and with quiet muttering.

"It started early on in development when we were determining the structure little by little in order to make the stages, and for some reason Nakago-san and Tezuka-san kept talking about coins," said director Yusuke Amano in a new Iwata Asks. Iwata characterized it as "muttering about coins," and Amano agreed. "They were both going on about how good it felt to get coins. It was just about the time that Super Mario 3D Land was finishing up, and in that game Mario can put a Question Block over his head."

The team said they wanted to include that in the game, but only a few coins would come out and they didn't find that satisfying. "So we made it so that if you dash, coins come out like crazy," Amano said. The game concept spun out from there, and the team agreed that a million coins seemed like a good "astounding" number to reach for.

But then a "big problem arose." The goal of getting a million coins became too insurmountable, and even replaying stages wasn't enough to reach such a large goal. So the team created other methods of getting more coins, like the Coin Rush mode, co-op play, and Street Pass features. The team also had to win over producer Shigeru Miyamoto, whose initial reaction to the Coin Head block power-up was simply: "I don't like it." He apparently changed his tune when they explained it as if it were a regular block that was stuck to Mario's head, rather than being bashed.

New Super Mario Bros 2 launches August 19; and speaking of coins, Nintendo is promoting its new digital initiative by offering double the Club Nintendo coins for buying a digital copy.