The Twilight Samurai

At the start of the film, the main character, Iguchi Seibei, becomes a widower when his wife succumbs to tuberculosis. His wife receives a grand funeral, more than what a lowest-ranking samurai such as Seibei could afford. Seibei works in the grain warehouse, accounting for stores inventory for the samurai clan. His samurai colleagues give him the condescending nickname "Tasogare Seibei" or "Twilight Seibei" when evening approaches, Seibei rushes home to look after his senile elderly mother and two young daughters, Kayano and Ito, instead of bonding with his supervisor and other samurai colleagues over customary nights of dinner, geisha entertainment, and sake drinking. Even though he is of samurai class, Seibei continues to neglect his own appearance, failing to bathe and dressing shabbily. The well-being of his young daughters and medicine for his mother take priority over new clothes or covering the monthly bath fee.Things change when Seibei's childhood friend, Tomoe (sister of Iinuma Michinojo, one of his better, kinder samurai friends) returns to town. Recently divorced from an abusive alcoholic husband, Koda, a samurai captain), Tomoe finds comfort and solace with Seibei's daughters. When her ex-husband Koda barges into the household of Michinojo in the middle of night in a drunken demand for Tomoe, Seibei accepts a duel with the captain, hoping to put a stop to the abuse. There seems little chance for him to beat the captain, but Seibei feels he must try. Dueling amongst clan members is strictly forbidden. The penalty is usually death for the winner as the loser is already dead. Seibei decides to use only a wooden stick whilst Koda brandishes a steel katana. Seibei overcomes Koda, sparing both their lives.When Iinuma Michinojo asks Seibei to marry his sister, he feels that Iinuma is teasing him for his strong feelings for Tomoe, like when he, Iinuma, and Tomoe were children. Iinuma knows Tomoe's feeling for Seibei, and Seibei is a kind man who would treat Tomoe better than Koda. With much deep regret, Seibei cannot accept Iinuma's offer of his sister's hand in marriage, citing his inferior social status and how he did not want to see Tomoe share the burden of poverty as Seibei struggles every month to feed Kayano and Ito whilst caring for his ailing mother. Seibei stoically regrets how his departed wife suffered in his care, who came from a higher samurai family. Iinuma talks no more of it. Tomoe stops seeing Kayano and Ito.In the final act, the head of Seibei's clan, having heard of his prowess with a sword, orders Seibei to kill a samurai retainer, Yogo Zen'emon, who has been "disowned" and who stubbornly refuses to resign his post by committing seppuku. The young lord of the clan has died from measles, and there is a succession struggle going on behind the scenes over who will be the new lord of the clan. Yogo ended up on the losing side of this conflict, hence his ordered suicide. Yogo killed a formidable samurai who was sent to kill him. Seibei is promised a rise in social standing if he accepts the dangerous mission. Seibei is very reluctant at first, requesting two days to think about it. He says that, because of great hardship in his life, he has lost all resolve to fight with ferocity. He needs two days to get himself up to the task. The new clan leader is furious over this answer and orders him removed from the clan. Seibei finally agrees to attempt the mission. Upon parting that evening, Seibei mentions the welfare of daughters to his supervisor. His supervisor promises him that he will make sure the girls will be taken care of if the worst comes to pass.The following morning, Seibei attempts to get ready, but there is no one to help him prepare in the rituals that are customary of samurai before battle. With no one to turn to, he asks Tomoe for her assistance. Before he leaves, he tells Tomoe that he was wrong not to propose marriage. He says that if he lives, he would like to ask for her hand in marriage now that there is promise of a promotion. She regretfully tells Seibei she has already accepted another man's proposal. Seibei, feeling like a fool, tells Tomoe to forget about the silly conversation. Tomoe says that she will not be waiting at his household for him to return. Seibei says he understands completely. He thanks Tomoe for her generosity for assisting him in this final ritual. They part.At Yogo's house, Seibei finds his target drinking in a dark, fly infested room. Yogo recognizes Seibei and invites him to sit and drink. He then asks Seibei to allow him to run away. He explains he was only faithfully serving his master and describes how both his wife and daughter also died of tuberculosis and only thanks to his master's generosity could he afford a proper funeral. Seibei commiserates and explains how he sold his katana to pay for his wife's funeral. He reveals that his scabbard contains a fake bamboo sword. This angers Yogo who believes Seibei is mocking him. Seibei explains he has been trained with the short sword, which he still carries, but Yogo is not placated.Seibei's kodachi fighting style is matched up against Yogo's ittry (single long sword) swordsmanship in an intense close quarters duel. Despite allowing Yogo to slash him several times, Seibei kills Yogo when his longer sword gets caught in the rafters. Despite his wounds, Seibei limps home. Kayano and Ito rush to him in the courtyard, happy to see him. Tomoe is still there, waiting in the house. They have an emotional reunion.In a brief epilogue, his younger daughter explains that their happiness was not to last: He died three years later in the Boshin War, Japan's last civil war. Ito often heard from fellow co-workers that Tasogare Seibei was a very unfortunate character, a most pathetic samurai with no luck at all.Ito disagrees: her father never had any ambition to become anything special; he loved his two daughters, and was loved by the beautiful Tomoe. [D-Man2010]

Question: What is the penalty for dueling amongst clan members?
Answer: death