The Siege of Castle Shimura was the battle for Castle Shimura, between the Mongol forces of Khotun Khan and the Japanese warriors under Lord Shimura, the jito of Tsushima island.
Siege[]
Seeking to retake his castle from the Mongols led by Khotun Khan and Straw Hat traitor Ryuzo, Lord Shimura asked his nephew Jin Sakai to gather allies across the island, including the Yarikawa clan, Lady Masako Adachi, Sensei Ishikawa, local thief Yuna, and Norio and his warrior monks. Lord Shimura also recruited the pirate Goro to smuggle a message to the Shogun asking for reinforcements. Once the Shogun's reinforcements arrived, Lord Shimura and his army approached Castle Shimura, and the siege began.
The battle began in the Attackers' favor, as the defenders were decimated by the onslaught of skilled warriors and pushed further into the keep. Jin's dishonorable tactics during the siege, such as beheading a Mongol leader to terrify his troops, disturb his uncle. Eventually, the attackers are able to push the Mongols into the inner keep. However, the Khan resorted to destroying the bridge to the inner keep with explosives, causing massive casualties on the samurai after Lord Shimura ordered a frontal charge.
Though Lord Shimura intends to repair the bridge and order another frontal charge at dawn, Jin knows that the tactic will result in more unnecessary loses for the Samurai, and proposes that he poison the Mongols instead. Lord Shimura deems this as an act of terror and demands that Jin reconsider, but Jin is filled with hatred at the Khan for the death of his friend (and Yuna's sister) Taka and defies his uncle. At night, Jin infiltrates Castle Shimura's inner keep and sneaks poison into the Mongols' food, which was being used for a feast. The tactic worked, and all of the Mongols were killed.
With the Mongols dispatched, Jin enters the inner keep to find and kill Khotun, but encounters Ryuzo instead. When Jin demands to know where the Khan is, Ryuzo explained to him that he had already left to campaign further north in Kamiagata, and made him stay behind to collect Jin's head. Ryuzo does not want to fight and asks Jin to lie to his people and tell them that he was his spy. Jin asks him to surrender and answer for his crimes, but Ryuzo, knowing that Lord Shimura would execute him on the spot, refuses and duels Jin a second time. Ultimately, Jin is victorious, killing Ryuzo.
As Jin leaves, Lord Shimura and his army enter the inner keep and see what Jin has done. Lord Shimura is furious at Jin's defiance, despite Jin's insistence that his way was the only feasible one and that the castle was taken bloodlessly. Knowing that the Shogun will want someone executed, Lord Shimura asks Jin to blame Yuna as a scapegoat, but Jin refuses and sends Yuna away to hunt the Khan. He is arrested for his crimes, but later escapes with help from Kenji.