UPDATE 2/4/15 0.15am: Nintendo has officially announced Pokémon Rumble World during its just-finished Nintendo Direct broadcast.
The game is headed to 3DS as a downloadable eShop title on 8th April and will be "free-to-start", with added content then available to buy in-game.
It's the first time that the Rumble spin-off series has featured free-to-play mechanics, although it follows in the footsteps of fellow free-to-play Pokémon spin-off Pokémon Shuffle, which arrived for 3DS last month and has since racked up more than 2m downloads.
Watch the Pokémon Rumble World announcement and first gameplay from the 25:30 mark below:
ORIGINAL STORY 31/3/15 3.25pm A recent ratings board listing has outed Pokémon Rumble World, an as-yet-unannounced title presumably bound for either 3DS or Wii U.
The game may be one of the reveals due in the next Nintendo Direct broadcast, which has been scheduled to take place at 11pm UK time tomorrow, 1st April.
Either way, we'll be reporting the major news as it happens (and we promise this isn't an April Fools').
Pokémon Rumble World looks to be again developed by Ambrella, the second-party studio responsible for the original WiiWare Pokémon Rumble, plus 3DS and Wii U sequels Rumble Blast and Rumble U.
The spin-off series centres around clockwork toy versions of the Pokémon critters, which can be made to fight each other.
Pokémon Rumble U introduced NFC figurine support to the series - a precursor to Nintendo's main Amiibo line. Perhaps a new sequel will work with a fresh range of Amiibo toys?