Based on the Results of Marine Meteorological and Oceanographical Observations (1966 ~ 1987), oceanographic conditions of the Japan Sea in winter was studied in relation to the Japan Sea Proper Water (JSPW). The mean and dispersion of the deep water above 1000 m depth are 0.26$pm$0.2$^{circ}C$ in temperature and 5.1$pm$0.25 ml/h in oxygen. The mean and dispersion of the bottom water below 1000m depth are 0.07$pm$$0.04^{circ}C$ in temperature and 5.1$pm$0.15ml/1 in oxygen. The distributions of the temperature and dissolved oxygen in the deep water above 1000m depth are ranged wider than 각one of the bottom water below 1000m depth in T-S and T-$ extrm{O}_2$ diagrams. The bottom water are showed more homogeneous and smaller variations than the deep water in the characteristics of water mass. The deep water above 1000m depth is active in contact with the atmosphere. The JSPW similar to the above characteristics is showed in the open ocean of the north of $40^{circ}$30""N, west of $138^{circ}$E. Therefore, the deep water is formed probably by the open-ocean convection.tion.