Here is a list of 3DS games that will be released in Japan:

(Thanks to Famitsu for the list)

AQ Interactive
Cubic Ninja


Konami
Asphalt 3D
Metal Gear Solid: Snake Eater
Project Love Plus for Nintendo 3DS
Winning Eleven Series
Pro Baseball Spirits Series


ASCII Media Works
Fish On


Capcom
Mega Man Legends 3 Project
Resident Evil Revelations
Resident Evil The Mercenaries 3D
Street Fighter IV 3D Edition



Koei Tecmo
Dead or Alive Dimensions
Samurai Warriors Chronicle


Square Enix
Chocobo Racing 3D
Leap Out! Puzzle Bobble 3D


Sega
Super Monkey Ball


Hudson
Deca Sports Extreme


Namco Bandai
Ace Combat 3D
Table Pen Sports
Tales of the Abyss
Pro Baseball Famitsa 2011
Ridge Racer R 3D


Marvelous
Animal Resort


Ubisoft
Combat of Giants
Ghost Recon Tactics
Splinter Cell 3D
Driver 3D


Level 5
Professor Layton and the Mask of Miracle


Nintendo
nintendogs + cats
Pilotwings Resort
Starfox 64 3D
Steel Diver
Kid Icarus: Uprising
The Legend of Zelda: The Ocarina of Time 3D
Animal Crossing
Paper Mario
Mario Kart