If you trace the food culture and history of Japan, there is a unavoidable relations between our land, abundant source of water and rice production.

Ever since the Japanese descendants had brought wet ricecultivation culture from China over 5,000 years ago, rice has always been the center of our diet and has been playing the essential role for the Japanese food culture. 
As a byproduct of rice, purely fermented alcohol drink from rice and water "sake" became a national alcoholic beverage of Japan since over 2,500 years ago. 

Because It was firstly produced within the shrines of Japan's oldest religion Shinto, Sake still is a key element of many Shinto rituals and Japanese festivals. 
Sake is linked to Japanese culture in many ways and expresses the beauty of Japanese nature, traditions, culture and whole spirit.

It is often pronounced "SAH-ki" by English speakers, yet in Japanese it is more like "SAH-KEH".
The word "Sake" in Japan simply means 'alcoholic beverage', In Japanese, we commonly specify the drink as "Nihonshu" or more official term "Seishu"