The newly formed bottom water in the Japan Sea was observed in the summer of 2001 after the severe winter 2000–2001. The new bottom water, which was observed in the northwestern Japan Sea, showed low temperature, high salinity, high dissolved oxygen and low nutrients concentration compared to the old bottom water. The distribution of the new bottom water indicates that the bottom water was formed in the south off Vladivostok, not in the northern Japan Sea north of 43°N, and was advected to the observation area. It is suggested that the formation event occurred in the late January-early February 2001, because strong flows of faster than 8 cms−1 appeared abruptly from mid-February 2001. This formation event may contribute not only the relaxation of the oxygen-decreasing trend in the bottom layer but also the spin-up of the thermohaline circulation in the Japan Sea.