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Ōhara Kō Detached Breakwater Lighthouse

Fl (2) Green 6s🇯🇵Isumi, JPOperational

Location & Light Range

About Ōhara Kō Detached Breakwater Lighthouse

This 12-meter cylindrical concrete post light stands at the end of a detached breakwater in Ōhara harbor, Chiba Prefecture, Japan. Attached to the post is a 1-story square equipment room, also constructed of white concrete. The structure guides vessels with a green light that flashes every six seconds. Its focal height reaches 14 meters, providing a geographic range of 11.6 nautical miles. The site is open to visitors by boat, but the tower itself is closed to the public, maintaining its operational status.

Why it matters: The light warns mariners of the detached breakwater's termination, preventing collisions and facilitating safe passage into Ōhara harbor, supporting local fishing and commercial activities.

Light & Optic

Characteristic Signature
Fl (2) Green 6s
Flash Type
Flashing
Light Color
Green
Flash Count
2 flashes
Interval
6s
Raw Code
Fl G 6s
Focal Height
14m
Geographic Range
11.6NM

Location

City
Isumi
Country
🇯🇵Japan
Region
Chiba Prefecture
Sea Region
Ōhara harbor, marking the end of a detached breakwater
Latitude
35.2567°
Longitude
140.4086°

References & Identifiers

Nearest Port
Katsuura, Chiba(8.3 km)
ARLHS No.
JPN-1329

Tower & Structure

Tower Height
12m
Tower Shape
cylindrical
Tower Color
white
Material
concrete

Structure: A 12m cylindrical concrete post attached to a square 1-story white concrete equipment room.

Visiting

Open to public
Site open, tower closed

Nearby Vessels

Flag
Type
Name
Dist.
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Frequently Asked Questions

How do mariners identify Ōhara Kō Detached Breakwater Lighthouse at night?+
Ōhara Kō Detached Breakwater displays the characteristic Fl (2) Green 6s — 2 green flashes every 6 seconds. Each lighthouse has a unique flash pattern published in the List of Lights, allowing mariners to positively identify it and distinguish it from other navigation aids in the area. The green color may indicate a specific sector or warning zone.
Which ports and harbors does Ōhara Kō Detached Breakwater Lighthouse guide vessels into?+
Ōhara Kō Detached Breakwater Lighthouse assists vessels approaching 5 nearby ports. The closest is Wakura at 7.6 NM to the SSW. Other ports served include Okitsu, Chiba (10.7 NM SW), Abuto (18.5 NM SW), Togane (18.7 NM N), Futtsu, Chiba (19.7 NM N). Mariners should consult the relevant chart for full approach and pilotage information.
Is Ōhara Kō Detached Breakwater Lighthouse still active and maintained?+
Yes, Ōhara Kō Detached Breakwater Lighthouse is currently operational. It is actively maintained and continues to emit its characteristic light signal for marine navigation. Most modern lighthouses are automated and monitored remotely by the national maritime authority.
What shipping routes pass near Ōhara Kō Detached Breakwater Lighthouse?+
Ōhara Kō Detached Breakwater Lighthouse is located within the Japan / Korea shipping lane — a busy shipping corridor linking the major ports of Japan and South Korea. This makes it an important navigation reference for commercial shipping traffic in the region.
How can I track vessels near Ōhara Kō Detached Breakwater Lighthouse?+
You can track vessels near Ōhara Kō Detached Breakwater Lighthouse in real time using MarineRadar. The platform shows live AIS positions of ships in the area, including vessel name, type, flag, speed, and course. Use the "Track Vessels Nearby" button on this page to open the live map centered on this lighthouse.