Katayamazu Onsen, Onsen resort on Lake Shibayama in Kaga, Ishikawa Prefecture, Japan

Katayamazu Onsen is a hot spring resort on the shore of Lake Shibayama, with mineral-rich thermal waters that rise from deep beneath the lake. The facility features indoor and outdoor bathing pools where guests experience the warm, healing waters.

In 1653 Maeda Toshiaki, second lord of the Daishōji domain, saw waterfowl gathering on Lake Shibayama during a falconry visit and concluded that hot water welled up from the lake bed. Domain-funded drilling failed to secure a source, and later attempts stalled for lack of money. In 1876 part of the lake was filled and an artificial island was bridged; the first inn opened in 1877 and a source was finally secured in 1882.

The public bathhouse here reflects Japanese bathing customs, where visitors bathe separately by gender and spend time in both indoor and outdoor pools overlooking the lake. The practice shows how onsen bathing remains central to local daily life and social habits.

The onsen town sits on the southwest shore of Lake Shibayama. From Kaga Onsen Station, the Canvas sightseeing bus reaches the bathhouse stops in 11 to 14 minutes; the sea-loop route takes about 60 minutes one way. By car it is about 5 minutes from Katayamazu IC. The former Kitama line to Awazu Station closed in 1965.

The onsen was discovered in 1653 when Maeda Toshiaki, second lord of the Daishōji domain, saw waterfowl gathering on Lake Shibayama and realised hot water welled up from the lakebed. Development failed for centuries because the source lay underwater; only after part of the lake was reclaimed in 1876 and a bridge built to the artificial island did bathing become possible, with the first source secured in 1882.