Yokoyama is brewed by Omoya Shuzo on Iki Island, Nagasaki Prefecture, where sake production was revived in 2018 by master brewer Taizo Yokoyama after the brewery tested more than 20 water sources before finding soft water suited to sake making. The brewery crafts sake using Yamadanishiki rice cultivated on the island itself, and in 2024 the Junmai Daiginjo Yokoyama Princess Michiko won the Grand Prix at the 7th Sake-1 Grand Prix organized by Matsuo Taisha, the first Kyushu brewery to earn that distinction. Omoya Shuzo also produces barley shochu under the Chingu label, drawing on Iki Island's centuries-old identity as the birthplace of barley shochu.
