Overview
Shinsaku Hasumi is the Sorcery Bureau’s Datenseki lab chief in Part 2. The lab fails. Shiba already knows whose eyes to hire. Hasumi comes to trust Kunishige, later lets Shiba steal ore, and resigns after the bureau accepts Mikaboshi ceasefire terms. He is the government half of the kiln: a man who learns the mineral is real work and then watches his institution decide a princess is a bargaining chip.
He is not Mashiro. Mashiro opposes taking stolen rock to a civilian smith and dies later to Ariu. Hasumi is the one who has to run the tests that fail until the civilian looks. He is not Joji. Joji is annoyed and ranked above the partners. Hasumi is the lab. When the lab becomes a political object, he leaves it.
The lab
About 250 kilograms of Datenseki are known. One pair of eyes ever made it safe. Hasumi’s job is the sentence before “one pair.” Fail, fail, fail, then a picky weapons dealer who will not sell to people he cannot stand. Trusting Kunishige is a scientific conclusion and a moral risk. Letting Shiba steal ore is the risk spent. Resignation is the receipt.
Chapters 125 through 129 refuse montage. Smelting, Fire, Smelting, Smelting, Ironworks. Hokazono talked to a real swordsmith. Hasumi is the bureau person who has to stand near that refusal. The mineral wants to pop the user. Kunishige nearly dies in chapter 129. Chiaki pulls him back. A lab chief who has already seen failure knows what the fire is. He cannot sign the ceasefire with a clean face. Giyu might trade Chiaki. The bureau might accept. Hasumi resigns.
Story role
The Irishima talks are a battlefield titled as meetings. Hasumi is the meeting’s technical officer. Without him the book would skip from “vein showed” to “smith looks” with no government embarrassment. The embarrassment is the point. Japan harvests Irishima. The Mikaboshi come back. The lab does not produce a usable weapon on schedule. Enchanted Blades enter at plus one year and five months because a civilian was hired after the schedule failed.
His resignation is the Bureau becoming an army becoming the Kamunabi, seen from the man who liked the work and hated the terms. Present-tense Kasen will later leak a smith’s address because he thinks blades are a path to order. Hasumi is the older version of a government scientist: he saw the ore, trusted the eyes, and left when the table offered a girl. The leak essay is Kasen’s disease. This page is the man who quit before that disease was the director’s job.
Notes
Shinsaku Hasumi (蓮水 晋作). Lab chief. Resigns. For the talks, see Part 2. For the vein, see Irishima’s vein. For the partner who said no to the theft, see Mashiro. Official chapters: VIZ / MANGA Plus.