Sanso are Kamunabi fortresses assigned to surviving wartime Enchanted Blade bearers after the Rokuhira raid and Ibuki’s murder. The logic is the Lifelong Contract: while the bearer lives, the Hishaku cannot fully sign the stolen steel. Lock the person, stall the ten. It works until it does not. Kokugoku is attacked. Senkutsuji is attacked. Subaru is relocated. The long book of Part 1, Sword Bearer Assassination, is the Sanso system meeting a method that had three years of practice. This page is the buildings. The Kamunabi page is the bureau that staffed them. The Hishaku page is the method.
Kokugoku Hot Spring
Uruha’s Sanso. The Kokugoku Steam Squad, including Fushimi and Smoke Axe, are the guard. Hishaku-hired Datenseki troops hit first. The squad beats them. Then Hiruhiko arrives. Blood Crane, mercenary sorcerers, a train, a kabuki house. The Steam Squad dies. Chihiro fights Hiruhiko so Hakuri can move Uruha toward Senkutsuji. Chapter 48 is titled for the squad. They get a name and a grave in the same week. That is how the bureau spends specialists: named, competent, insufficient. The Anti-Cloud Gouger Special Forces were the same sentence in the first book.
Senkutsuji Temple
Samura’s Sanso, in the sense that a blind Buddhist swordsman and three Masumi are the Kamunabi’s idea of a vault. Pine-sorcery hirelings attack. The Masumi suppress sound and scent. Hakuri delivers Tobimune through Storehouse. Samura clears the temple. Then he cuts Uruha down. Suzaku: kill the contract, keep the man. The Hishaku think they have a partner who will eliminate bearers. He is lying about the dying. Owl goes up nationwide. The temple is no longer a Sanso. It is a launch site for a detection technique and a betrayal that is also a rescue. Ro, Moku, and Sumi leave with a different job: Iori.
The ones not on the page yet
Subaru Urita is moved rather than used as bait. Duplication sorcery makes a contract-opening assassination a poor match; kill one Subaru, another still holds the unnamed blade. Akemura is not in a Sanso. He is in a cell under HQ, which is a fortress of a different kind, the kind a director can leak around and a Vessel can split. Magatsumi’s master key is why that cell exists: if Akemura dies, the other wartime bearers die. Sanso without the basement is incomplete logistics. The basement without Sanso is a myth. Kasen wanted the steel. The buildings were the compromise until he sold the smith.
Chihiro’s deal after the Rakuzaichi (Hakuri as logistics, Magatsumi to the state, Enten in his hand) assumes Sanso can be used as a circuit rather than a prison: touch a bearer, Storehouse the blade, do not siege the mountain. The Hishaku assault on a fortress is what makes the table deploy that circuit in a hurry. The next book starts on a train because a building failed. Locations: locations. Arc: Sword Bearer Assassination. Surviving unnamed bearer: Subaru.