Nintendo of America has snapped up the domain SuperMario4.com.
The web address currently acts as a redirect: try to access SuperMario4.com in a browser and you'll be warp-piped to the official Nintendo US website.
Nintendo has already announced a new side-scrolling Mario game for release on 3DS by the end of the financial year - April 2013.
A return to Mario's numbered roots fits a move back to the series' origins. A fourth numbered Super Mario title would follow NES classic Super Mario 3, launched way back in 1988.
The upcoming 3DS side-scroller will mark a change of pace from the last major Mario title to launch. Mega-selling Super Mario 3D Land, a cross between classic Mario games and the more recent Galaxy sub-series, has sold over five million copies since its launch late last year.
But Super Mario 4 may be a confusing moniker in Japan. In 1990, Super Famicom classic Super Mario World was released with "Super Mario 4" as a subtitle.