Matsuya Brewery is located in Fujioka City, a land surrounded by three rivers in Gunma Prefecture. "Ruka (流輝)" is a limited distribution sake. It is crafted by Hiroyuki Matsubara, the sixth-generation owner and brewmaster. The name "Ruka" was considered for his child, and it embodies the meaning of "a sake that shines (輝) and flows (流)" and a sake to be cherished like his own child.