Iodake

Mt. Io (硫黄岳いおうだけ) is a 2,760-meter peak near the center of the Yatsugatake Range. The massive cliff formation on its north side (commonly called the “explosion crater”) is spectacular, and the summit sits at a key junction along the ridgeline connecting Mt. Yokodake and Mt. Akadake to the south with Mt. Tengu to the north. It is popular for traversing the central and northern Yatsugatake, and is also well-suited for beginner-to-intermediate alpine hikers.

Routes include the trail from Minotoguchi via Akadake Kosen to the summit area, the trail from Sakuradaira/Natsuzawa Kosen via Akaiwa-no-Atama, and the ridgeline traverse connecting Mt. Akadake and Mt. Tengu areas.

This page introduces bus access to Minotoguchi and to Inako Tozanguchi / Inako-yu. For access from similar trailheads, see also Akadake, Yokodake, and Tengudake.

*Timetable last checked: [sc name=”updated_date”][/sc]

Map

1. Going: Chino Sta. → Minotoguchi

From JR Chuo Main Line Chino Station West Exit Platform 4, take the Alpico Kotsu Minotoguchi Line bus and get off at the terminal Minotoguchi.
Fare: ¥1,900 (revised Aug 2025)
Travel time: Approx. 38 min
Operating days: Weekends & holidays (additional services in summer)

Bus Timetable: Minotoguchi Line (to Minotoguchi)

Reference: Alpico Kotsu Minotoguchi Line (Chino Sta. – Minotoguchi)

2. Going: Takebashi Sta. → Minotoguchi (Mainichi Alpen-go)

From Mainichi Shimbun Bldg. near Takebashi Station (Tokyo Metro), take the Mainichi Alpen-go express bus to Minotoguchi (seasonal overnight service, reservation required).

Approximate schedule: Depart Takebashi 22:30 / Shinjuku 23:00 → Arrive Minotoguchi around 4:30–5:10. Some services include early-morning rest options. Check the official website for the latest details.

Reference: Mainichi Alpen-go (Outbound) / Yatsugatake Return

3. Going: Koumi Sta. → Inako Tozanguchi → Inako-yu

From JR Koumi Line Koumi Station, take the Koumi Town Bus toward Inako-yu. Get off at Inako Tozanguchi Iriguchi or continue to the terminal Inako-yu.
Season: Approx. April 19 – late November, 2025. Note: in winter, many services do not run all the way to Inako-yu.

Bus Timetable: Koumi Sta. → Inako Tozanguchi → Inako-yu

Reference: Koumi Town Bus / Timetable (revised Apr 2025)

4. Return: Minotoguchi → Chino Sta.

From Minotoguchi, take the Alpico Kotsu Minotoguchi Line bus to Chino Station.
Fare: ¥1,900
Travel time: Approx. 38 min
Operating days: Weekends & holidays (additional services in summer)

Bus Timetable: Minotoguchi → Chino Sta.

Reference: Alpico Kotsu Minotoguchi Line (Chino Sta. – Minotoguchi)

5. Return: Minotoguchi → Shinjuku Sta. (Mainichi Alpen-go)

From Minotoguchi, take the Mainichi Alpen-go express bus to Shinjuku (seasonal service, reservation required).

Approximate schedule: Depart Minotoguchi 15:40 → Arrive Shinjuku 18:45 → Tokyo Sta. 19:15. Check the official website for the latest details.

Reference: Mainichi Alpen-go (Yatsugatake Return)

6. Return: Inako-yu → Inako Tozanguchi → Koumi Sta.

From Inako-yu or Inako Tozanguchi Iriguchi, take the Koumi Town Bus to Koumi Station.
Season: Approx. April 19 – late November, 2025. Note: in winter, many services do not run all the way to Inako-yu.

Bus Timetable: Inako-yu → Inako Tozanguchi → Koumi Sta.

Reference: Koumi Town Bus / Timetable (revised Apr 2025)