It's an upcoming game for Nintendo DS, featuring characters from all the previous Sakura Taisen games. Looks somewhere between a Sakura Taisen game and Pokemon Mystery Dungeon (a roguelike with party-forming).
Info:
http://uk.ds.ign.com/objects/906/906344.html
Trailer:
http://www.youtube.com/watch?v=ehXdnx4VQmA
Official Site:
http://game.sakura-taisen.com/ds/
