Japan's Three Famous Onsen: Arima, Kusatsu, Gero

The Edo-period monk Hayashi Razan ranked Japan's hot springs the way a sommelier ranks wines — and the three he placed at the top are still the ones people argue over.

Nihon Sanmeisen

The grouping of Nihon Sanmeisen — the three most famous hot springs of Japan — is traditionally attributed to the Confucian scholar Hayashi Razan in the early 17th century, who identified Arima, Kusatsu, and Gero as the finest onsen in the country. Each occupies a different corner of Honshu and offers a distinct bathing experience: Arima's rare mineral waters, Kusatsu's intensely acidic spring, and Gero's famously silky water.

An overnight stay at a traditional ryokan — with multi-course kaiseki dinner, in-house baths, and tatami bedrooms — is the classic way to experience each. All three towns also offer day-trip bathing options for travelers short on time or budget.

1. Arima Onsen (Hyogo) — the oldest

Arima is Japan's oldest documented hot-spring town, with records of imperial visits reaching back more than a thousand years. Tucked into the mountains behind Kobe, it is famous for two water types bathed in alternation: kinsen ('golden spring'), heavy with iron and salt and the color of rust-brown tea, and ginsen ('silver spring'), a clear carbonated and radon water.

• ●Water type — iron-salt kinsen and clear carbonated ginsen
• ●Access — about 30 minutes by subway and Hokushin / Kobe Dentetsu lines from central Kobe; roughly 60 minutes from Osaka
• ●Price range for ryokan — commonly ¥20,000–50,000 per person per night with two meals

2. Kusatsu Onsen (Gunma) — the strongest

Kusatsu is defined by its yubatake — the 'hot-water field' at the center of town where sulphurous spring water is cooled through long wooden troughs before being piped to the inns. Kusatsu's water is one of the most acidic in Japan (pH around 2.1), strong enough to peel paint and famously effective for skin conditions. The traditional yumomi water-stirring performance remains a tourist highlight.

• ●Water type — highly acidic sulphur-chloride spring, among the strongest in Japan
• ●Access — JR limited express Kusatsu-Shima from Ueno to Naganohara-Kusatsuguchi (~2.5 hr), then JR bus to the yubatake (~25 min)
• ●Price range for ryokan — roughly ¥15,000–40,000 per person per night with two meals

3. Gero Onsen (Gifu) — the softest

Gero sits deep in the mountains of Gifu Prefecture, on the rail line between Nagoya and Takayama. Its alkaline water (pH around 9) is often described as bijin no yu — 'beauty water' — because it leaves the skin feeling smooth. The town itself is compact and walkable, with three free public footbaths and one open-air riverside bath along the Hida River.

• ●Water type — simple alkaline hot spring, gentle on the skin
• ●Access — JR limited express Hida from Nagoya to Gero Station (~90 minutes)
• ●Price range for ryokan — roughly ¥15,000–40,000 per person per night with two meals

Comparing the three