Kawagoe Castle was once an important defensive and administrative post on the approaches to Edo. Most of it is gone, but the Honmaru Palace remains: a low, timber building with tatami rooms, corridors, and a formal audience space that gives a clear sense of how a domain lord's headquarters worked away from the battlefield.
It is a quieter visit than the warehouse district, and that is part of its value. The building asks you to slow down and notice proportion, screens, wood grain, and the practical dignity of a castle that was more office than fortress.