Carbonaceous matter (CM) with various modes of occurrence has been observed in quartz veins in the biotite zone of the Ryoke metamorphic belt in the Yanai district, Yamaguchi Prefecture, SW Japan. Raman spectroscopic analysis of the CM revealed that high temperature fluids had percolated through fractures, which were now occupied by the quartz veins that had formed during the retrograde stages of metamorphism. These fluids may have also affected the degree of organization of the fine-grained CM particles in the host pelitic rocks and the coarse-grained particles that had precipitated from them at a later stage.