Direct water mass renewal through convection deeper than 1000 m and the independent process of dense water production through brine rejection during sea ice formation occur at only a limited number of sites globally. Our late winter observations in 2000 and 2001 show that the Japan (East) Sea is a part of both exclusive groups. Japan Sea deep convection apparently occurs every winter, but massive renewal of bottom waters through brine rejection had not occurred for many decades prior to the extremely cold winter of 2001. The sites for both renewal mechanisms are south of Vladivostok, in the path of cold continental air outbreaks.