Except for the Otsuke-garo (the Karo assigned directly by the shogun) and the Karo for gosankyo (three privileged branch families of the Tokugawa family), there was a fundamental rule that ordinary Karo officers were not entitled to have an audience with the shogun as they were not direct retainers of the Tokugawa shogun family.
家老は、徳川御三家の御附家老や、御三卿付きの家老を除き、徳川将軍家の陪臣であるから、将軍に謁見の資格がないのが大原則である。