Shochu is the other Japanese indigenous alcoholic drink, but unlike sake it is distiled and contains 25% to 40%, sometimes more, alcohol. It can made from almost any kinds of vegetables or fruit. I even found one made from Shiitake mushrooms called « Asadachi » (« Asadachi » is what happens to healthy men when they wake up!)
But for people who want a more complete explanation, by all means refer to John Gauntner’s great website!
As I said before, try Shizuoka Schochu made from rice first. It is comparatively sweet and definitely the best of its kind!