Nintendo has trademarked the name “Delta Emerald” in Japan.
The mark was filed on May 2 and made public on May 29.
Earlier this month, Nintendo announced it was developing Pokemon Omega Ruby and Pokemon Alpha Sapphire, remakes of the GameBoy Advance originals for 3DS.
Pokemon Emerald was, of course, the third game to follow Ruby and Sapphire, but a remake has not been announced.
Thanks, Hachima Kikou.