Koumi Line

The Koumi Line runs 78.9 km from Kobuchizawa in Yamanashi Prefecture to Komoro in Nagano, around the eastern foot of the Yatsugatake mountains. Between Kiyosato and Nobeyama it crosses 1,375 metres, the highest point on any JR line in Japan, and Nobeyama, at 1,345.67 metres, is the highest JR station. The nine highest stations on the whole JR network are all on this line, one after another.

It is a single-track local line, worked by one- and two-car diesel railcars that stop everywhere. From the plateau it drops down the valley of the Chikuma River into the Saku basin and ends at the old castle town of Komoro. JR East calls it the Yatsugatake Kōgen Line, the highland line, and on most Fridays, weekends and holidays it runs HIGH RAIL 1375, a sightseeing train named for the summit.

Eight trains a day run the whole way in each direction, taking a little over two hours. Sit on the left leaving Kobuchizawa for the Yatsugatake.

Trains leave Kobuchizawa, a junction on the Chūō Line, and swing round a long curve to start climbing at once. Through woods and holiday villages they reach Kai-Koizumi, Kai-Ōizumi and Kiyosato, the highland resort, already above 1,000 metres. On a clear day Mt Kaikoma and the Southern Alps stand behind, and the Yatsugatake rise ahead.

Over the summit

Beyond Kiyosato the woods open onto the Nobeyama plateau, a high, flat country of lettuce and cabbage fields. At 1,375 metres the line crosses the highest point on the JR network, where trains run slowly; it is also a watershed, with rivers on one side running to the Pacific and on the other to the Sea of Japan. A few minutes later the dishes of the radio observatory appear through the trees, and the train stops at Nobeyama, the highest JR station.

Down the Chikuma

From Shinano-Kawakami the line drops into the valley of the Chikuma River, which it crosses seven times before Koumi, the town at the middle of the line that gave it its name. The valley widens past Yachiho and Usuda, and at Nakagomi, where the railcars are based, the line has become a commuter railway through the Saku basin. It runs on a viaduct over the Hokuriku Shinkansen at Sakudaira and alongside the Shinano Railway into Komoro.

The trains

Most trains are KiHa 110 railcars, the green-and-cream diesels that replaced older stock from 1991. Some services are KiHa E200, which when they arrived in 2007 were the world's first hybrid railcars in passenger service. HIGH RAIL 1375 is a pair of cars rebuilt from KiHa 100- and 110-series railcars, painted silver and blue with the Yatsugatake under the stars. The line climbs at up to 33 in 1,000, and even the fastest local takes over two hours.

Eight local trains a day run the whole line in each direction, every day of the year, with the same times at weekends. They stop at every station and need no booking. More trains run only between Komoro and Nakagomi or Koumi at the busy northern end. HIGH RAIL 1375 runs as a rapid on its operating days, with long stops at Nobeyama.

Kobuchizawa to Komoro

Komoro to Kobuchizawa

Good to know:

• HIGH RAIL days, autumn 2026. Most Fridays to Mondays and holidays until 30 November: 2–5, 9–12, 16–19, 24–25 and 30–31 October; 1–3, 6–9, 13–16, 20–23 and 27–30 November. JR East had not yet published the winter dates. Every seat is reserved.
• The Nobeyama stops. HIGH RAIL 1 waits 18 minutes at Nobeyama; HIGH RAIL Hoshizora arrives at 19:58 and stays over forty minutes for the stargazing. The times above are departures.
• Maintenance days. On 13–15 October, 17–19 November and 15–17 December 2026 the 10:07 and 13:37 from Kobuchizawa and the 08:16 and 12:00 from Komoro do not run, nor the midday short trains to and from Nobeyama.
• Weekend extras. On weekends and holidays until 18 October the Yatsugatake Kōgen Ressha adds extra trains from Kobuchizawa to Nobeyama and back.

Times as of October 2026, from JR East's timetable. Check your date on JR East's Kobuchizawa station timetable (opens in a new tab).

The local trains need only an ordinary ticket, priced by distance: ¥1,600 from Kobuchizawa to Komoro, half for children. Buy it at the station before boarding; IC cards such as Suica work only at Kobuchizawa, Kiyosato and Nobeyama, so a paper ticket is simpler for the whole line. The trains are driver-only.

HIGH RAIL 1375 also needs a reserved seat, ¥840, half for children. Seats go on sale at 10:00 one month before travel, at JR ticket offices and machines and on JR East's online booking site; every seat is reserved. Fares checked October 2026 against JR East's timetable and its March 2026 fare table; Japanese yen.

The Koumi Line is a JR East line, and the JR passes cover it end to end, HIGH RAIL 1375 included. The JR EAST PASS, ¥35,000 for five days, covers every JR East line, and so does the Japan Rail Pass, ¥50,000 for seven days. A pass holder still needs a seat reservation for HIGH RAIL 1375, which is free with the pass.

For this journey alone, a pass is not worth buying: the whole line costs ¥1,600, and ¥2,440 with a HIGH RAIL seat. It pays when the Koumi Line is one day of a longer trip. Kobuchizawa is on the Chūō Line from Shinjuku, and Sakudaira, near the northern end, is on the Hokuriku Shinkansen back to Tokyo, so the line makes a loop out on one and back on the other; price that loop as single tickets before buying a pass.

Checked October 2026 against the JR EAST PASS (opens in a new tab) page, JR East's HIGH RAIL 1375 page and the Japan Rail Pass prices (opens in a new tab).

With a train every two hours or so, a stop costs a morning or an afternoon, so pick one or two: the distillery or the highland resort at the southern end, the observatory and the summit at Nobeyama, the castle park at Komoro to finish.

A night at Kobuchizawa puts you on the morning trains up to the summit. Kiyosato is the place to stay among the highlands, and Komoro, at the end of the line, is a short walk from the castle park and on the Shinano Railway towards Karuizawa.

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