SN 393 is the modern designation for a probable supernova that was reported by the Chinese in the year 393 CE. An extracted record of this astronomical event was translated into English as follows: A guest star appeared within the asterism Wěi during the second lunar month of the 18th year of the Tai-Yuan reign period, and disappeared during the ninth lunar month. The second lunar month mentioned in the record corresponds to the period 27 February to 28 March 393 CE, while the ninth lunar month ran from 22 October to 19 November 393 CE. The bowl-shaped asterism named Wěi is formed by the tail of the modern constellation Scorpius. This asterism consists of the stars in Scorpius designated ε, μ, ζ, η, θ, ι, κ, λ and ν. The guest star reached an estimated apparent magnitude of −1 and was visible for about eight months before fading from sight, whose lengthy duration suggests the source was a supernova. However, a classical nova is not excluded as possibility.