Yubatake, also known as the "Hot Water Field," is a popular attraction located in the heart of Kusatsu Onsen, a hot spring resort town in Gunma Prefecture, Japan. It is a unique and natural phenomenon that draws thousands of visitors each year.

The Yubatake is essentially a large open-air mixing basin for two of Kusatsu Onsen's hot springs, which combine to form one of Japan's most acidic hot spring waters. The water temperature is around 50 degrees Celsius and contains high levels of sulfur, which gives it a distinct yellowish-green color and a strong, pungent odor.

The hot water from the springs is channeled into wooden troughs and allowed to cool down, which allows minerals like sulfur to precipitate out, forming a milky-white sediment. This sediment is then harvested and dried in the sun to form small, powdery flakes known as yunohana, which are believed to have therapeutic benefits.

Yubatake is surrounded by traditional inns, restaurants, and souvenir shops, making it a popular destination for tourists to experience the Japanese onsen culture. Visitors can also walk around the Yubatake, take pictures, and even soak their feet in the hot spring water, which is available in several footbaths nearby.