What Is Hakojima Retarding Basin? A Scenic Waterside Spot with Views of Mount Tsukuba
Hakojima Retarding Basin (Hakojima Yūsui-chi) is a scenic waterside spot located in Iida, Chikusei City, Ibaraki Prefecture.
A retarding basin is an area designed to temporarily hold floodwater when rivers swell due to heavy rain.
Hakojima Retarding Basin was developed after the Kokai River flood caused by Typhoon No. 10 in August 1986 (Shōwa 61), and today it is known as one of the best viewpoints of Mount Tsukuba (Tsukuba-san).
For travelers, the highlight is the chance to enjoy a waterside landscape with Mount Tsukuba in the background.
Around 290 cherry trees line the perimeter of the pond, and in spring you can take in the blossoms, the water surface, and the mountain all in one view.
A walking path of about 1.4 kilometers circles the basin, so even a relaxed loop takes only around 30 minutes.
Rather than a bustling commercial attraction, this is a quiet place to savor the changing moods of nature at your own pace.
Sakasa Tsukuba: How to Catch the Reflection on the Water Surface
One of the most famous sights at Hakojima Retarding Basin is the "Sakasa Tsukuba," or the inverted reflection of Mount Tsukuba.
Sakasa Tsukuba refers to the scene where Mount Tsukuba is mirrored on the surface of the water.
The calmer the water, the more clearly the twin silhouettes of Nantai-san and Nyotai-san (the two peaks of Mount Tsukuba) appear in the reflection.
That said, the view depends heavily on weather, wind, and the state of the water surface.
Early mornings with little wind are considered the best time to see Sakasa Tsukuba, as the water tends to settle like a mirror.
Since the same scene cannot be guaranteed on every visit, it is best to approach it with a relaxed mindset, enjoying nature's chance moments.
When taking photos, including not just the mountain but also the color of the sky, ripples on the water, and the cherry trees along the shore will help capture the gentle atmosphere unique to Hakojima Retarding Basin.
Cherry Blossoms in Spring and the Changing Light of Morning and Evening
Hakojima Retarding Basin shows a different face depending on the season and time of day.
In spring, around 290 cherry trees planted around the pond combine with Mount Tsukuba to create a memorable landscape.
The best time to see the cherry blossoms is typically from late March to early April. When peak bloom coincides with a calm morning, you can photograph Sakasa Tsukuba and the cherry-lined shore reflected on the water at the same time.
Rather than viewing the flowers up close, looking at them from across the water creates a wider, more expansive scene.
The hours when the morning sun catches the water and the evening sky glows red are also great times for striking photos.
In summer, the contrast between the lush green rice paddies and Mount Tsukuba stands out, while in autumn, clearer air often reveals sharper mountain outlines, giving the basin a different look in every season.
However, footing can be hard to see in the very early morning or evening.
If you are traveling in an unfamiliar area, it is safer to arrive while it is still light and to keep your walk within a comfortable range.
What to Know Before Going to See Diamond Tsukuba
Hakojima Retarding Basin is also known as a spot where you can see "Diamond Tsukuba," the moment when the sun rises near the summit of Mount Tsukuba.
Diamond Tsukuba is said to occur twice a year, around February 14 and around October 28.
Sunrise times vary by season, but in mid-February it is generally around 6:50 a.m.
When the light is reflected on the water, the scene is sometimes called "Double Diamond Tsukuba."
For Double Diamond Tsukuba to appear, the sky must be clear with very transparent air, and the surface of the basin must be perfectly still.
If you plan to include it in your travel itinerary, it is a good idea to check the date and weather in advance.
Crowds of photographers often gather on these days, so if you are using a tripod, please choose a spot that does not block the walking path.
Each year, people start claiming spots more than 30 minutes before sunrise during the Diamond Tsukuba period, so an early arrival is recommended if photography is your goal.
Etiquette and Tips for International Visitors
Hakojima Retarding Basin is both a place to enjoy scenery and a waterside area that plays a role in flood control.
When walking around, please always follow any "no entry" signs or on-site instructions.
The ground can be unstable in places close to the water.
Take care not to get so absorbed in photography that you step too near the edge of the pond.
The surrounding area also includes farmland and local roads, so avoid taking photos on the roadway or entering private property.
Please take your trash with you, and if you visit early in the morning, keep voices and engine noise low so that local residents feel comfortable welcoming visitors.
On winter mornings, temperatures can fall below freezing, and a phenomenon called "kearashi" (a steam fog that rises from the water) may form.
Warm clothing, gloves, and non-slip shoes are recommended.
Facilities and Restrooms: Practical Information Before Your Visit
Hakojima Retarding Basin is a place for enjoying natural scenery and does not have tourist-style facilities.
Public restrooms and vending machines can be hard to find right next to the basin, so it is wise to bring drinks and snacks in advance.
If you need a restroom, check nearby parks a short distance away.
Wi-Fi and multilingual signage are also limited, so international travelers will benefit from preparing offline maps and translation apps.
While the basin gets busy with photographers during the Diamond Tsukuba season, it is usually quiet, making it an ideal spot for a peaceful walk.
Basic Information to Check Before You Go
Hakojima Retarding Basin is located in Iida, Chikusei City, Ibaraki Prefecture.
If traveling by train, the nearest station is Kuroko Station on the Kantō Railway Jōsō Line, about 5 minutes by car (taxi).
On foot, it takes roughly 25 to 30 minutes.
If driving, using the route from the Kuroko Station direction makes it easier to locate the basin.
When using car navigation, one common method is to set "Kawakubo Shin-Nōson Shūraku Center (Tsuji 381-1, Chikusei City)" as the destination.
There is a free parking area with space for about 70 cars.
The surroundings are not packed with large tourist facilities, so checking the location on a map in advance will make your trip smoother.
The site is free to visit.
However, conditions can change due to weather, events, or temporary notices.
Especially during the Diamond Tsukuba season, it is a good idea to check ahead for information on crowds and parking.
Summary: Enjoying the Many Faces of Mount Tsukuba from a Quiet Waterside
Hakojima Retarding Basin is a spot where you can slowly take in the scenery created by Mount Tsukuba and the water.
From Sakasa Tsukuba and around 290 cherry trees in spring to sunrise and sunset scenes and the twice-yearly Diamond Tsukuba (around February 14 and October 28), the way you enjoy it changes with the season and time of day.
Rather than a destination for major activities, it is best suited to a quiet trip where you walk the 1.4-kilometer path and watch the natural scenery shift around you.
For international travelers, it is also a place to feel the relationship between the Ibaraki plains and Mount Tsukuba.
Following local guidance and etiquette, please enjoy the gentle scenery that only Hakojima Retarding Basin can offer.
