Chris Morgan (Wanted) and Hossein Amini wrote the script for this adventure, based on the true story of 47 warriors who sought vengeance from the tyrant who banished them from his kingdom. Ken Watanabe had also been mentioned for a part in 47 Ronin, although Universal Pictures said his involvement was only a rumor. The producers will continue to seek out Japanese actors to stay true to this tale.
Rinko Kikuchi is best known for her Oscar-nominated performance in Babel, along with her character Bang Bang in The Brothers Bloom. Tadanobu Asano will next be seen in Thor and Battleship, while Hiroyuki Sanada portrayed Dogen in the last season of Lost. Kou Shibasaki is primarily known in Japan as a singer, although she appeared in the Japanese movies Battle Royale, One Missed Call, and several others.