Ryeo's answer came back in four days.
He left a folded note in the secondary notebook Kang Min kept on his lab bench, slid under the cover at some point during a session when Kang Min was at the forge bay and not at his seat. The note was in Ryeo's personal shorthand, which Kang Min had been reading for months from the margins of working documents left open at adjacent benches. Short, precise, and written in the assumption that the recipient could parse it without annotation.
