Katanuma

What it is

• A highly acidic volcanic lake located within Kurikoma Quasi-National Park
• A former sulfur mining site that operated until 1968
• A body of water with a pH level of approximately 2.4
• A natural habitat for acid-tolerant midges and diatoms rather than fish

What to see

• Water that changes between emerald and blue depending on the weather
• Fumaroles on the lakebed that emit volcanic gases like hydrogen sulfide
• A walking path that allows visitors to circle the entire lake
• A rest house and rental boats available for use on the water

Getting there

• The lake is located two kilometers from Naruko-Onsen Station

Notes written by Japan Gems from facts in Japanese Wikipedia.