Nintendo Co.’s Switch sales doubled in Japan on the release of a Super Mario edition of the console, a surprise boost for the six-year-old console that’s pivotal to the gaming firm’s bottom line.

Consumers in Japan bought 110,241 units of the Switch console last week, doubling the amount from the prior week, according to data from market tracker Famitsu. The crimson-red Mario edition went on sale on Friday, and it juiced sales in much the same way that Legend of Zelda and Splatoon custom editions have done over the past year and a half.

The surge, late in the console’s life cycle, shows the depth of fan loyalty for Nintendo’s games. The special edition comes decorated with motifs and icons from the Super Mario universe, but is otherwise no different from the regular OLED model in terms of computing power and storage space. The Kyoto-based hardware and software maker is releasing a new title in the franchise — Super Mario Bros. Wonder, out on Oct. 20 — that could further push up the themed gadget’s sales.

“The numbers they seem to be putting up are surprising considering it’s the same device with a different plastic cover,” Bernstein analyst Robin Zhu said.

Nintendo aims to sell 15 million Switch units globally in the fiscal year to March, which would mark a 17% drop from the previous year. Zhu and analysts including Hideki Yasuda of Toyo Securities expect sales to surpass Nintendo’s typically conservative estimate.

Nintendo got off to a flying start this year with a new Legend of Zelda game and Zelda-themed Switch hardware in the April-June quarter. Mario’s Hollywood movie released in the same quarter was a record breaker at the box office and helped propel hopes for further Mario-related merchandise doing well this year. The weak yen is also likely to have a positive impact on Nintendo’s earnings.

Read more: Nintendo Powers to Record Profit on Zelda Debut, Mario Movie