It has been generally recognized that five different word classes were distinguished as to the accent-patterns in the past, and the classes have since partially merged in different ways in different dialects. However, there has been discovered only one dialect so far in which the original five classes have been retained down to the present day, i.e., Ibukijima dialect in the Inland Sea of Seto. The dialect is very important in the sense that it is expected to shed new light on how the original accent system actually sounded. The author has investigated the dialect, and has proposed a new phonological interpretation of the accent system: he posits three accent types (rising, falling, and level) and one lowering accent kernel. This paper is added with copious list of words.