Sep–NovTwo museums side by side on Lake Mikata. One displays 45 m of lake mud that became the planet's reference for dating the last 50,000 years; the other, what people living on the same shore left behind 6,000 years ago.
The bed of Lake Suigetsu holds about 45 m of finely layered mud laid down without a break over roughly 70,000 years. Each year adds a light and a dark band about 0.7 mm thick, a varve (年縞). Count the layers and you have a calendar; measure the carbon-14 in leaves trapped between them and you can see how radiocarbon ages drift from calendar years. In 2012 the record was adopted into the international calibration curve, and scientists worldwide now use it.
No large river flows straight into Suigetsu, so Lake Mikata upstream catches the sediment. The lake is deep and its bottom water holds little oxygen, so nothing churns the mud. Hills shelter it from wind. And the basin is slowly sinking along a fault, so in 70,000 years it has never filled up.
The real core, all 45 m, sliced thin, backlit and mounted along a long gallery like stained glass. You walk backwards through 70,000 years, with markers for volcanic ash layers from known eruptions, the end of the Ice Age and the start of the Jōmon period. Opened 2018.
Finds from the Torihama shell mound, a lakeside Jōmon settlement a few hundred metres away, excavated between 1975 and 1985. The site was waterlogged, so wood, rope, seeds and lacquer survived: archaeologists call it the "Jōmon time capsule".
Highlights: two cedar dugout canoes (1981 and 1982 finds; the first is 6.08 m long), red-lacquered bowls and a replica of the famous red lacquered comb, about 6,000 years old. A piece of lacquer-tree wood from Torihama, dated to about 12,600 years ago, is the oldest yet found.
| Varve Museum | Jōmon Museum | |
|---|---|---|
| Hours | 09:00–17:00 (last entry 16:30) | 09:00–17:00 (last entry 16:30) |
| Closed | Tuesdays (open in Golden Week and summer holidays), 29 Dec–2 Jan | Tuesdays, New Year |
| Adult | ¥500 | ¥500 |
| Combined ticket | ¥700 (school age ¥280) | ¥700 |
| Getting there | JR Mikata + 5 min taxi, 10 min bike, 30 min walk | Same; 70 shared parking spaces |
By car: about 5 minutes from Mikata Goko Smart IC on the Maizuru-Wakasa Expressway. 122-12-1 Torihama, Wakasa town.
Things first-time visitors usually wish they'd known.
Lake Suigetsu's bed holds 45 m of annual layers laid down over about 70,000 years. In 2012 the record was adopted into the international radiocarbon calibration curve, making it the world standard for turning radiocarbon ages into calendar years.
¥500 for adults, or ¥700 combined with the Jōmon Museum next door. 09:00–17:00, closed Tuesdays. Visitors aged 70 and over enter free with ID.
JR Obama Line to Mikata (31 minutes from Tsuruga, ¥510), then 5 minutes by taxi, 10 by rental bike or 30 on foot.
The lakeside and coast around Mihama are 10–20 minutes away by car.
Onsen hotel with big-window baths over Wakasa Bay, five minutes by car from JR Mihama. The closest good hotel to the Rainbow Line.
Small luxury inn on a calm bay: infinity bath over Wakasa Bay, guji in summer and farmed tiger fugu in winter. Free shuttle from Obama Station at 14:30.
Opened 2022 beside the Shinkansen terminus. The best rail base for day trips along the Obama Line, or a late arrival from Tokyo.