Major Waterways of Japan

Japan's mountainous geography creates short, steep rivers and numerous lakes.

Major Rivers (by Length)

1. Shinano (Chikuma): 367 km — Nagano, Niigata
2. Tone: 322 km — Gunma, Saitama, Ibaraki, Chiba (Kanto Plain lifeline)
3. Mogami: 229 km — Yamagata, Akita
4. Kiso: 229 km — Nagano, Gifu, Aichi, Mie
5. Yodo: 75 km (from Lake Biwa) — Kyoto, Osaka, Hyogo (Keihanshin water supply)

Major Lakes

1. Lake Biwa (Shiga): 670 km² — largest, ancient (~4M yr), water source for 14M
2. Lake Kasumigaura (Ibaraki): 168 km² — 2nd largest, brackish
3. Lake Inawashiro (Fukushima): 103 km³ — 3rd, volcanic
4. Lake Towada (Aomori/Akita): 61 km² — caldera, deep (327 m)
5. Lake Kussharo (Hokkaido): 79 km² — largest caldera lake

Major Straits

• Tsugaru Strait: Honshu-Hokkaido (Seikan Tunnel)
• Kanmon Strait: Honshu-Kyushu (bridge, tunnel, ferry)
• Akashi Strait: Honshu-Shikoku (Akashi Kaikyō Bridge—world's longest suspension)
• Kurushima Strait: Shikoku islands (Kurushima-Kaikyō Bridges)
• Bungo Strait: Kyushu-Shikoku

Rivers: steep, flood-prone, heavily engineered (dams, levees). Lakes: volcanic/tectonic origin. Straits: critical transport links.