In 1634, the conference system was changed to a system where each of the three councilors would take turns on a monthly duty system and six assistants (predecessors of junior assistants system) were appointed to support the business of the councilors.
寛永16年（1634年）には制度を改め、年寄り3人の担当を月番制とし、六人衆（若年寄の前身）をその補佐として置いた。