A map of the Sigma Draconis system
Sigma Draconis VII was the seventh planet in the Sigma Draconis system. (TOS: "Spock's Brain")
While in command and recording his only log entry in TOS, Sulu inadvertently called Sigma Draconis VI "Sigma Draconis VII". Kirk also inadvertently refers to Sigma Draconis VI as "Sigma Draconis VII" in his own later captain's log, even though he himself referred to the planet as "VI" twice earlier in the episode.