13 Assassins (DVD is available for rent, in Japanese with fairly decent English sub)
A 2010 Japanese samurai movie. Directed by Takashi Miike. 141 min.
The story is set towards the end of Edo era. Shougun's brother, Lord Naritsugu is a psychotic evil, and so one of the senior government officials secretly order his assassination. The movie tells how the assassination was executed by a group of 12 samurai worrier plus one commoner, by attaching him and his entourage on their journey from Edo back to his homeland.
The movie got 96% rating on Rotten Tomato, and I agree with the rating. It's a well made movie. The first half of the movie shows how 13 of them were gathered, and how they planed the attack, and the last half of the movie, shows how they executed the attack, with final hour filled with gritty fighting scenes.
The movie is not for everyone, but if you like samurai movie, this one is one of the best-made in recent years, IMO.