Gunkan-bugyō (軍鑑奉行), also known as kaigun-bugō, were officials of the Tokugawa shogunate in Edo period Japan.
[1] Conventional interpretations have construed these Japanese titles as "commissioner", "overseer" or "governor".
The creation of this new position was an administrative change which was deemed necessary because of two treaties which were negotiated with the Americans.
The open port provisions were part of the Convention of Kanagawa of 1858, which cam about as the result Commodore Perry's second appearance in Tokyo harbor with armed battleships.
The prefix kaibō-gakari meaning "in charge of maritime defense" was used with the titles of some bakufu officials after 1845.