Holding about 25% of the U.S. sake market, Gekkeikan is one of the most famous sake producers on earth.
The 370-year-old secret is the neighborhood of Kyoto that Gekkeikan lives in, called Fushimi. The Kyoto Project explains:
Fushimi is an ideal place for sake brewing because of its natural environment. Appropriate temperatures and good-quality water are required to brew sake. In Fushimi, both of these important factors exist.
The city of Kyoto is set in a basin, surrounded by mountains on the north, east, and west. These mountains keep Kyoto very chilly in wintertime. A cool temperature of around 5? is important to mature sake in a brewery. So cold winter temperatures created by Kyoto’s natural basin is why sakebrewing became so deeply rooted here.
To learn (and taste) firsthand, visit the Gekkeikan Sake Museum the next time you're in Kyoto.