What is Japanese Iced Coffee?

Japanese iced coffee is simply coffee brewed with hot water, directly onto ice.  One-third of the liquid is in the form of ice and the other two-thirds in the form of pour-over.

What makes Japanese iced coffee different from just adding ice to hot coffee?  As you pour the hot water over the coffee grounds, it extracts a wide range of tasty flavors and aromatics from the ground coffee.  As it drops onto the ice cubes, the ice cubes instantly lock those flavors by flash-chilling at the same time diluting the concentrate.

Source: https://www.justonecookbook.com/japanese-iced-coffee/