Sightseeing in Hitachinaka: Burial Mounds, a Furnace and Dried Sweet Potatoes by the Sea

What Kind of City Is Hitachinaka?

Hitachinaka is a city in the central part of Ibaraki Prefecture, just east of Mito. It was born in 1994 from the merger of Katsuta and Nakaminato. Former Katsuta prospered as an industrial town and former Nakaminato as a port town serving as the outer harbor of Mito, so the city has two different faces, and the overlap of the two in a single city is its hallmark.

This article introduces the city’s sights from north to south, in descending order of latitude. We start with a flower-covered hill, then head south through seaside shrines, Cretaceous reef rocks, ancient tombs and the remains of a late-Edo factory. Though the city is known for its flowers, time from the Kofun period to the early modern era lies layered beneath the ground.

1. Hitachi Seaside Park (国営ひたち海浜公園)

Hitachi Seaside Park is a national park by the sea in Hitachinaka, covering as much as 350 hectares. The first roughly 70 hectares opened in 1991, and the park has been expanded many times since. About 215 hectares, roughly 60 percent of the total, are currently in use as a park. Managed by a national agency, it is Ibaraki’s leading flower destination.

The landscape of flowers spreading across the hillsides is famous, with daffodils and tulips around April, nemophila around May, and kochia (summer cypress) around October each reaching its peak season. Planting of nemophila began in 2002, and trial planting of kochia began in 2005. These two flowers have now become the face of the park.

On the other hand, the past of this land is not so well known. In 1938 the Army’s Mito Flying School and airfield were built here, and in 1946, after the war, the site was used by the U.S. military as a bombing and gunnery range. The vast site was returned to Japan in 1973. In this site’s view, that the flat plateau once used for military training and bombing has become a place where countless flowers sway in the wind makes you feel the size of the time this land has carried. Peak bloom times shift from year to year, so please check the timing before you go.

2. Horiide Shrine and Hoshiimo Shrine (堀出神社とほしいも神社)

Horiide Shrine is in Ajigaura-cho, Hitachinaka, standing on high ground overlooking the Pacific. It is said to have been founded in 1663 in the Edo period. When neighboring villages were disputing a boundary, a domain official surveying the site found a hollow surrounded by a double water fence, and digging there turned up swords and spears. The domain judged this to be the true body of the nearby Isosaki Myojin, and tradition says it came to be enshrined as the village’s guardian shrine. The shrine’s name is said to come from this tale of something being “dug out” (horidasu).

The main hall was completed in 1671, and the domain lord Tokugawa Mitsukuni is said to have dedicated a sacred mirror. In recent years the shrine has drawn attention for another reason: its link to dried sweet potatoes (hoshiimo). Ajigaura is said to be where Terunuma Kantaro first succeeded in making dried sweet potatoes in Ibaraki Prefecture, in 1895. To honor that achievement, “Hoshiimo Shrine” was founded in 2019 as an auxiliary shrine within the grounds.

A monument honoring them has been erected within the grounds, listing five people who worked to spread dried sweet potatoes as “gods of hoshiimo.” Among them are a man who learned techniques from Shizuoka and turned them into a business, and an agronomist who strove to increase sweet potato production. Behind Ibaraki’s rise to first place in dried sweet potato output lies the long effort of such people. Since this is an active shrine, please walk quietly and follow the guidance in the grounds.

3. Sakatsura Isosaki Shrine (酒列磯前神社)

Sakatsura Isosaki Shrine stands on a hill on a cape jutting into the sea on Hitachinaka’s eastern coast, and is counted as a Myojin Taisha, a high rank among the shikinai-sha shrines recorded in ancient texts. Its main deity is Sukunabikona no Mikoto, and it is thought to be closely tied to Oarai Isosaki Shrine across the Naka River, the two shrines said to form one faith together.

As for the shrine’s founding, a Heian-period record states that a deity appeared on the Oarai shore in 856, and Sukunabikona is said to have been enshrined at Sakatsura. The name “Sakatsura” is said to come from a place name, “sakatsura” (reverse line), because among the surrounding coastal rocks that tilt south, a portion tilts north, and it later came to be written “酒列” with the sense of a god of sake. The shrine buildings were once lost in the medieval period, but in the early modern era the Mito domain lord Tokugawa Mitsukuni began rebuilding, and the next lord relocated and restored it at the present site.

Above the worship hall are carvings of a squirrel and grapes, said to be the work of the master carver Hidari Jingoro. On both sides of the approach grow broadleaf trees such as camellia, tabu-no-ki and sudajii, which are designated a Natural Monument of Ibaraki Prefecture. Scenic spots associated with the Mito domain and the Hiraiso coast are also nearby, so together with the shrine you can touch the history of the seaside. Since this is an active shrine, please walk quietly and keep the stillness of the sacred precinct.

4. Torazuka Kofun (虎塚古墳)

Torazuka Kofun is a keyhole-shaped burial mound in Nakane, Hitachinaka, and is designated a National Historic Site. It is thought to have been built near the end of the Kofun period, in the early 7th century. It measures about 63 meters in total length including the surrounding ditch, and in the round rear section there is a stone chamber built of fitted stones, on whose walls paintings in red pigment remain.

On the walls, which are of stone coated with white clay, geometric patterns and items such as swords, shields and quivers are painted in red pigment, and it is regarded as the leading painted-mural tomb of eastern Japan. When excavated in 1973 the chamber was found unopened, and measuring the air and humidity inside was reportedly a first in Japan. A facility to preserve the chamber has now been built to prevent the mural from deteriorating.

The area around the mound has been developed as a historic park. However, entry into the stone chamber is restricted, and it is opened to the public only during limited periods in spring and autumn. What did people about 1,400 years ago entrust to the color red? The answer is not known, but in this site’s view, it may have held not only a display of the buried person’s authority but also a prayer to protect the dead. Opening times change from year to year, so please check in advance.

5. Jugoroana Cave Tombs (十五郎穴横穴群)

The Jugoroana Cave Tombs are a group of yokoana tombs in Nakane, Hitachinaka, very close to Torazuka Kofun. They are graves made by digging holes into a plateau cliff, and are thought to date from the end of the Kofun period to the Nara period. Surveys through fiscal 2014 confirmed 272 tombs, and the total is estimated to exceed 300. Regarded as one of the largest cave-tomb groups in eastern Japan, they were designated a National Historic Site in February 2024.

The group consists of three sub-groups: the Sashibuchi district, where Torazuka Kofun stands, the Tatede district and the Kasaya district. Excavated items include magatama beads, cut-glass beads and Sue ware, as well as swords with metal fittings and small knives, and one knife has been pointed out as resembling an item preserved at the Shosoin. These items are kept at the city’s Buried Cultural Properties Research Center.

The name “Jugoro” is said to come from a legend that the brothers Soga Juro and Goro once hid and lived here. In fact these are ancient graves, but people of later times looked at the holes and linked them to a famous story. Each hole is a place where someone was once buried, so please spend your visit quietly, do not climb the cliff or holes, and follow the guidance.

6. Hiraiso Coast (平磯海岸)

The Hiraiso Coast runs from Isozaki to Hiraiso in Hitachinaka, and is lined with reef rocks of the Nakaminato Group, a Cretaceous stratum. This stratum consists of sandstone and mudstone alternately layered on a sea slope about 80 million years ago, then gently tilted by later uplift and eroded by waves so that only the soft parts have been deeply gouged. The result is a unique landform often called the “Devil’s Washboard.”

The coast is also known as a fossil site. Fossils of ammonites, sea urchins, bivalves and sharks, and even mosasaurs, have been found, and it is especially famous for the clusters of heteromorph ammonites with unusual shapes. It is also the first place in Ibaraki Prefecture where Mesozoic strata were confirmed. About 330 square meters of coast south of Seijoseki Rock is designated a Natural Monument of the prefecture.

Highlights of the coast include Seijoseki, said to have been named by Tokugawa Mitsukuni, and Chikushoiwa, a rock tilting south, the opposite of its surroundings. Though they are natural formations, the fact that the lords of Mito recognized their value and gave them names suggests the long relationship between this coast and people. The rocks are slippery and you need to watch the tides. Please do not take away or damage the Natural Monument rocks and fossils; simply look.

7. Nakaminato Reverberatory Furnace Site (那珂湊反射炉跡)

The Nakaminato Reverberatory Furnace Site lies within Azumagaoka Park in Sakae-cho, Hitachinaka. This is where the Mito domain in the late Edo period built reverberatory furnaces to cast iron cannon for coastal defense against foreign ships. Tokugawa Nariaki borrowed a large sum from the shogunate to undertake the construction, and the first furnace was completed in 1855 and the second in 1857.

About 20 cannon were made here and set up in various gun emplacements. However, the furnaces were destroyed in the Tengu Party rebellion before they could be fully operated. Even so, the project became the trigger for modern ironmaking in Kamaishi, Iwate, and some researchers regard it as the starting point of Japan’s iron industry. Today a reconstructed model of the furnace stands in the park.

The park also has the Sanjomon gate, relocated from the Mito domain’s Edo residence. It was once a gate for receiving imperial envoys, and it is said that people who passed through it included Sakuma Shozan and Saigo Takamori. Nearby is an Inari shrine rebuilt to pray for the furnace’s safety, and a story remains of the friendship between the carpenter Tobita Yoshichi and the brick craftsman Fukui Senkichi. It is a human story of engineers that is said to have appeared in prewar textbooks. The surroundings of the site are close to residential areas, so please visit quietly.

Local Specialties: Food and Drink

Hitachinaka’s specialty is, above all, dried sweet potatoes (hoshiimo). The city’s output of dried sweet potatoes is said to be the highest in Japan, and Ibaraki Prefecture accounts for about 90 percent of national production. Dried sweet potato making in Ibaraki is said to have begun with Terunuma Kantaro of Ajigaura in 1895, and around 1908 the method was brought to Nakaminato from Shizuoka and full-scale production began. It is explained that soil suited to sweet potatoes and the dry winter climate were well suited to making them.

Its other face is the seafood typical of a harbor town. There are the ports of Nakaminato, Hiraiso and Isozaki, where bonito and other fish are landed. Seafood processing was once thriving, and processing of boiled octopus is said to have held about one-third of the national share at its peak. In recent years, however, as catches have declined, raw materials for processing have increasingly come from imports.

Both foods are tied to the local climate and history. Because flavor and processing methods differ from shop to shop, comparing them yourself on a visit is part of the fun.

Rare Wildlife and Nature

Hitachinaka’s natural highlights are its coastline and flower hills. The Cretaceous reef rocks of the Hiraiso Coast and the camellia and tabu-no-ki grove along the approach to Sakatsura Isosaki Shrine are designated Natural Monuments of the prefecture. At the Ajigaura swimming beach, sand tends to decrease because of the effects of harbor development in the area, and work to replenish the sand is carried out every year.

The flower scenery of Hitachi Seaside Park is also part of the city’s nature. However, this flower field was made by human hands on a flat plateau once used for war. It can be called a landscape born where nature and human activity overlap.

The Naka River flows along the south of the city, and Nakaminato, the harbor at its mouth, flourished as the outer port of the Mito domain. Its geography, at the place where river meets sea, has shaped the history of this town.

Other Notable Things About This City

Within Hitachinaka is a place name, “Takeda.” This land is said to be the birthplace of the Takeda clan of Kai Genji. In the Edo period it became Mito domain territory, and Nakaminato flourished as Mito’s outer port. Scenic spots tied to the lords of Mito still dot the seaside.

In the modern era, many Hitachi Ltd. factories were built in Katsuta and industry flourished. However, there is also the history of Katsuta being shelled from warships at the end of the Pacific War. Such events lie beneath today’s calm streets. At memorial sites and war remains, please spend your time quietly and respectfully.

In Nakaminato, the “Minato Hassaku Festival” is held every other year. A historic festival representing the city, it features lavish festival floats, and the performing art “Shishi to Miroku” is a nationally selected Intangible Folk Cultural Property. In the 2011 Great East Japan Earthquake, a maximum intensity of upper 6 was recorded in the city, which also suffered tsunami damage. The history of a harbor town facing the forces of nature is also part of this town’s true face.

The Night Side: Ghost Stories and Haunted Spots of This City

So far we have walked Hitachinaka’s daytime face: a hill of flowers, seaside shrines wrapped in myth, Cretaceous reef rocks, ancient tombs and the remains of late-Edo cannon-making. Each place layers the time of people who lived there, prayed there, and sometimes paid a great sacrifice.

That depth connects to the night side as well. In a town that holds burial mounds, cave tombs, former military land and the history of a harbor, there may be ghost stories and rumors passed down, but this article does not touch on specific places and does not recommend searching for them. In this site’s view, a ghost story is something like a shadow that a land’s history and people’s prayers have cast on people’s minds. Old burial grounds and historic sites are still important places, and one should refrain from entering them at night.

At KARASU CHANNEL, we present true ghost stories and haunted spots not so that you can visit them but so that they are recorded. After getting to know the daytime scenery, please read the night stories too.

Before You Go

Opening hours, fees, closing days and access change easily, so they are not included in this article. Before you go, please check the latest information on the official website of each facility or local government. Some places may be restricted from entry because of weather or disasters.

Frequently Asked Questions

Q. In what order should I see Hitachinaka’s sights?

A. This article introduces them from north to south. Grouping by area makes it easier: the seaside park in the north, the eastern coast (Ajigaura, Hiraiso and Isozaki), the burial mounds of Nakane, and Nakaminato in the south. Because of the distances, please check your means of travel in the official guides of the city or the tourism association.

Q. What is Hitachinaka’s specialty food?

A. Dried sweet potatoes are the best known. Seafood such as bonito and Nakaminato’s processed seafood products are also known. Shops that handle them change, so please check the latest information before you go.

Q. Can I see inside the burial mound’s stone chamber?

A. Entry into the stone chamber of Torazuka Kofun is restricted, and it is opened to the public only during limited periods in spring and autumn. Whether it is open and its schedule change from year to year, so please check the official guide of Hitachinaka City.

Official sites and references consulted
https://ja.wikipedia.org/wiki/ひたちなか市
https://ja.wikipedia.org/wiki/国営ひたち海浜公園
https://ja.wikipedia.org/wiki/堀出神社_(ひたちなか市)
https://ja.wikipedia.org/wiki/酒列磯前神社
https://ja.wikipedia.org/wiki/平磯海岸
https://ja.wikipedia.org/wiki/虎塚古墳
https://ja.wikipedia.org/wiki/十五郎穴横穴群
https://ja.wikipedia.org/wiki/那珂湊反射炉
https://ja.wikipedia.org/wiki/干しいも