The differences are in how they are made. Wine is made using single fermentation. Grapes, wine’s main ingredient, contain monosaccharides. There is no need to saccharify the juice. The winemaker need only add yeast.
Japanese sake is made through multiple parallel fermentation. The rice used to make Japanese sake doesn’t contain simple sugars. So, in a single container, saccharification of starches by koji mold enzymes and the conversion of sugar to alcohol by yeast proceed side by side. This is called multiple parallel fermentation.