[en] In 1995 and 2000, the radiocarbon ratio (Δ¹⁴C) of total dissolved inorganic carbon was measured in the Japan Sea where deep and bottom waters are formed within the sea itself. We found that (1) since 1979, the Δ¹⁴C in bottom water below about 2000-m depth in the western Japan Basin (WJB) had increased by about 30 per mille by 1995, and (2) the bottom Δ¹⁴C in the WJB did not change between 1995 and 2000. The former finding was due to penetration of surface bomb-produced radiocarbon into the bottom water owing to bottom ventilation, whereas the latter was caused by stagnation of the bottom ventilation there. In the eastern Japan Basin (EJB), the bottom Δ¹⁴C also increased by about 30 per mille between 1979 and 2002. Recent stagnation of the bottom ventilation in the EJB is also suggested from analyses of constant bomb-produced tritium between 1984 and 1999. The temporal variations of Δ¹⁴C, tritium, and dissolved oxygen in the bottom waters indicate that: (1) new bottom water is formed south of Vladivostok in the WJB only in severe winters; and (2) the new bottom water then follows the path of a cyclonic abyssal circulation of the Japan Sea, which results in the increases in dissolved oxygen and the transient tracers in the bottom waters in the EJB and Yamato Basin with an approximate 3- to 6-year time lag. This process is consistent with the spatial variations of Δ¹⁴C, bomb-produced ¹³⁷Cs, and chrofluorocarbon-11 in the bottom waters of the Japan Sea. (author)