This article primarily surveys several phenomena that are derived from the asymmetry between CjV and CwV in the Japanese language: the historical processes of Sino-Japanese forms CjV and CwV, the vowel coalescences of Vu and Vi (iu, eu vs. ui, oi), the contracted forms having CjV, etc. Secondly, we discuss the relationship between the asymmetry of the two medial approximants j, w and the characteristics of the Japanese vowel system that give rise to another asymmetry between palatalization and labialization. Finally, we mention residual issues on the asymmetry of two medials, mimetic expressions having medial j and w, the history of the w-consonant, and so on.
