Oike Spring Water Group Oita Prefecture | Complete Guide to Mysterious Spring Water Spot Selected for Japan’s Top 100 Waters
The Oike Spring Water Group (oike yuusui gun) located in Asono, Shonai Town, Yufu City, Oita Prefecture is a clear and pure spring water group that flows from the northern side of Mount Kurogane (elevation 1,586m) at the eastern foot of the Kuju Mountain Range. It has been certified by the Ministry of the Environment as one of Japan’s Top 100 Waters and as one of the “Toyono Country’s Top 15 Waters,” and centered around Oike at an elevation of 850m, a mystical landscape surrounded by virgin forest unfolds.
This article comprehensively introduces information you should know before visiting, from the charm of the Oike Spring Water Group to specific access methods, how to collect water, surrounding walking courses, and precautions to take during your visit.
Overview and Characteristics of the Oike Spring Water Group
Why It Was Selected for Japan’s Top 100 Waters
The background to the Oike Spring Water Group’s selection for Japan’s Top 100 Waters lies in its abundant spring water volume and excellent water quality. Groundwater naturally filtered over a long time by the virgin forest of Mount Kurogane flows out, boasting an astonishing water volume of an average of 14 tons per minute and approximately 20,000 tons per day.
The water quality is calcium bicarbonate type with extremely high transparency, and the water temperature remains stable at approximately 12-13 degrees Celsius throughout the year. This clear water has a history of being used as domestic water and agricultural water for local residents since ancient times, and today it remains a valuable water source that many people visit to collect water from.
Role as a Source of the Asono River
The Oike Spring Water Group serves an important role in supporting the ecosystem of the Asono River, one of the tributaries of the Oita River system. The water that flows out becomes the Asono River and flows downstream, forming a rich wetland environment while merging with the Oita River.
Virgin forest composed of broad-leaved trees such as beech and maple spreads across this source region, and a valuable natural environment where diverse flora and fauna inhabit is conserved. Particularly during the season of new greenery and autumn foliage, you can enjoy the beautiful scenery created by forest and clear stream.
Charm of the Mysterious Blue Spring
The greatest feature of Oike is its mysterious blue water color. The center of the pond deepens, and the water flowing out from there reflects sunlight to create an illusory scene that glimmers in emerald blue and cobalt blue.
Because of the extremely high water transparency, you can see all the way to the bottom of the pond, and it is possible to observe spring water welling up while stirring up sand. This beautiful scenery continues to captivate visitors and boasts high popularity as a photography spot.
Access Methods to the Oike Spring Water Group
Access by Car
The Oike Spring Water Group has no bus service, so car access is the basic means of transportation. It is located approximately 30-40 minutes by car from Yufuin Onsen, accessed via National Road 621 (Yamanami Highway) and then National Road 40.
Travel time from major cities:
- From Yufuin Onsen: Approximately 30-40 minutes
- From Beppu City: Approximately 50-60 minutes
- From Oita City: Approximately 1 hour 30 minutes
- From Fukuoka City: Approximately 2 hours 30 minutes
A free parking space is available at the Oike Garden Area. However, parking may become congested on holidays and during autumn foliage season, so visiting during early hours is recommended.
Tips for Setting Navigation
When searching with navigation, set it to “Oike Spring Water Group” or “Oike Garden Area.” If searching by address, input “Asono, Shonai Town, Yufu City, Oita Prefecture.”
Because it is in a mountainous area, cellular signal may be weak in some sections. It is advisable to confirm the route in advance using a map app and download offline maps.
Road Conditions and Precautions
The road leading to the Oike Spring Water Group has winding sections characteristic of mountain roads. Particularly during winter (December-March), there is the possibility of snow accumulation and freezing, making the installation of studless tires or carrying of chains necessary.
Roads may be closed to traffic due to bad weather or after snowfall, so it is recommended to check road information from Yufu City or Oita Prefecture before visiting.
Facilities and Admission Fees of Oike Garden Area
Admission Fee and Operating Hours
Admission to Oike Garden Area requires a cooperation fee of 100 yen per person (as of 2024). This cooperation fee is used for the maintenance of walking trails and conservation activities of the natural environment. Fees are paid at a reception desk at the forest entrance.
Operating Hours:
- Basically accessible during daylight hours
- During winter, early sunset is recommended, visiting by 3 PM
- Avoid entering at night due to danger
Facility Equipment
The following facilities are developed at Oike Garden Area:
Water Collection Site: There is a dedicated space for collecting spring water, allowing you to take water away in plastic bottles or poly tanks. If drinking the water, boiling is recommended, and each person should judge and take responsibility accordingly.
Restroom: Public restrooms are installed near the parking area. Since it is in a mountainous area, it is recommended to use them before visiting.
Walking Trail: Developed walking trails surround Oike, allowing you to enjoy forest bathing while walking. The time required is approximately 15-20 minutes if walking only around the pond.
Walking Courses and Attractions of the Oike Spring Water Group
Basic Walking Course (Time Required: Approximately 30 Minutes)
From the parking area to Oike, a walking trail through virgin forest is developed. Walking approximately 5-10 minutes while feeling the chilly forest air, you will arrive at Oike.
Walking Highlights:
- Forest Bathing in Virgin Forest – Rich forest environment created by broad-leaved trees such as beech, maple, and oak
- Oike’s Blue Spring – Mysterious emerald blue water surface and the appearance of spring water
- Famous Water Falls – Small waterfall created by clear stream flowing from Oike
- Asono River Source – The beginning of a clear stream with high transparency
Hiking Course (Mount Kurogane Trail)
Oike Garden Area is also known as the starting point for Mount Kurogane climbing. For those wishing to enjoy full-scale hiking, a climbing trail to the mountain summit (elevation 1,586m) is developed.
Mount Kurogane Climbing Course:
- Time Required: Round trip approximately 5-6 hours
- Difficulty: Intermediate level
- Elevation Gain: Approximately 736m
- Precaution: Climbing equipment and sufficient water and food are necessary
From the trail, you can view the magnificent scenery of the Kuju Mountain Range, and alpine plants such as Miyama Kirishima can be observed near the summit.
Barrier-Free Information
Because Oike Garden Area is a facility utilizing natural mountain terrain, it is not fully barrier-free. The walking trail from the parking area to Oike has stairs and steps, making wheelchair movement difficult.
However, the path to the water collection site near the parking area is relatively flat, making water collection possible even for those with walking concerns. It is recommended to check details with facilities such as the Beppu/Oita Barrier-Free Tour Center before visiting.
Tips for Collecting Water and Precautions
Water Collection Method
At the Oike Spring Water Group, spring water can be collected at a dedicated water collection site. Many people visit carrying empty plastic bottles or poly tanks.
Water Collection Procedure:
- Prepare a clean container (plastic bottle, poly tank, etc.)
- Wait your turn at the water collection site (may be crowded on holidays)
- Fill the container with spring water
- Close the lid firmly
Precautions Regarding Drinking
Although selected as one of Japan’s Top 100 Waters by the Ministry of the Environment, this does not guarantee suitability for drinking. If consuming the spring water, please note the following:
- Boiling before drinking is recommended
- When drinking raw water, do so at your own responsibility
- Stop use if you experience any physical changes
- Not suitable for long-term storage, so use quickly
If concerned, it is recommended to check water quality information with Yufu City Hall or the health center.
Water Collection Etiquette
Water collection is an act of sharing a precious local resource. Please follow the following etiquette:
- Collect only the necessary amount (avoid taking large quantities)
- Do not pollute the water collection area
- Remember consideration for other visitors
- Always take trash with you
Optimal Seasons for Visiting and Clothing
Charm of Each Season
Spring (March-May):
The season of new greenery, when freshly budded leaves are beautiful. The difference between water temperature and air temperature can create mist around the spring water, allowing you to enjoy a mystical scene.
Summer (June-August):
The cool environment at elevation 850m is ideal as a summer resort. You can refresh both body and mind with forest bathing and negative ions from the clear stream. Caution is necessary for water activities due to low water temperature.
Autumn (September-November):
Known as a famous autumn foliage spot, with peak viewing from late October to early November. The contrast between broad-leaved trees tinted red and yellow and the blue spring is spectacular.
Winter (December-February):
Roads may be closed to traffic due to snow accumulation. On days when visiting is possible, the combination of snowy landscape and clear stream is beautiful, and you can enjoy a serene atmosphere. Cold protection measures are essential.
Clothing and Belongings
Basic Clothing:
- Easy-to-walk shoes (trekking shoes or sneakers)
- Easy-to-move clothing
- A light outer layer even in summer, as the elevation is high
- Hat (sun protection)
Belongings Checklist:
- Container for collecting water (if necessary)
- Drinking water
- Towel
- Insect repellent spray (spring-autumn)
- Camera
- Garbage bag
- Rain gear (weather changes easily)
Surrounding Spots and Combined Sightseeing
Yufuin Onsen
Yufuin Onsen, a representative hot spring in Oita Prefecture, is located approximately 30-40 minutes by car from the Oike Spring Water Group. A plan to relax and ease fatigue in a hot spring after sightseeing is recommended.
The Yufuin Onsen district features stylish cafes and restaurants and souvenir shops, with tourist attractions such as Kinrin Lake also well-developed.
Kuju “Yume” Grand Suspension Bridge
A pedestrian-only suspension bridge boasting the highest height in Japan, located approximately 40 minutes by car from the Oike Spring Water Group. The view of the Kuju Mountain Range from a height of 777m is breathtaking.
Chojabaru Visitor Center
A facility where you can learn about the nature of the Kuju Mountain Range and climbing information. Combined with the Oike Spring Water Group, it is ideal for deeply understanding the nature of Kuju.
Kurokawa Onsen (Kumamoto Prefecture)
Kurokawa Onsen, located further along the Yamanami Highway, also has good accessibility from the Oike Spring Water Group. Located approximately 50 minutes by car away, a stay in the atmospheric hot spring town is also recommended.
Precautions When Visiting the Oike Spring Water Group
Rules for Natural Environment Protection
The Oike Spring Water Group is a precious natural environment. Please follow the following rules:
- Always take trash with you
- Plant collection is prohibited
- Do not enter the pond, do not swim
- Do not speak loudly (consideration for wildlife)
- Do not go beyond designated walking trails
- If bringing pets, use a leash
Safety Precautions
- Walking trails are slippery when wet, so be careful
- Weather can change suddenly, so carry rain gear
- Avoid visiting alone; travel with multiple people
- Be aware that cellular signal is weak in some areas
- There is possibility of encountering wild animals such as bears, so carry a bell
Tips for Avoiding Crowds
Holidays and autumn foliage season attract many tourists. For those wishing to enjoy nature quietly, the following times are recommended:
- Weekday visits
- Early morning (around 8-9 AM)
- Before evening (around 3-4 PM) *Pay attention to sunset during winter
Summary: Enjoy Oita’s Nature at the Oike Spring Water Group
The Oike Spring Water Group, one of Japan’s Top 100 Waters that Oita Prefecture is proud to offer, is a natural spot featuring abundant spring water volume and a mysterious blue spring. Despite being only 30-40 minutes by car from Yufuin Onsen, you can refresh yourself in a quiet environment surrounded by virgin forest, forgetting the hustle and bustle of the city.
The sight of clear water flowing out at a rate of 20,000 tons per day is spectacular, and the landscape of forest and clear stream that show different faces in each season continue to captivate visitors. Water collection, forest bathing, photography, hiking—the Oike Spring Water Group offers various ways to enjoy itself. Please be sure to visit.
It is a special place where you can experience the blessings of natural mineral water nurtured by Oita’s abundant nature with all five senses. When visiting, do not forget to consider the natural environment, and let us work together to preserve this precious water source for the future.
