The Castle Seized by Satake Yoshinobu through an Assassination Plot(Kashima-jō, Hitachi Province – present-day Ibaraki)

2026-04-102026-05-10

A Hirayama Castle Overlooking a Great Torii Gate

Sunday, May 21, 2023.

Hello, this is Shin.

This time, I visited Kashima-jo, located in Kashima City, Ibaraki Prefecture 🚙

Originally, this castle was built by the Kashima clan of the Hitachi Heishi.

However, during the Sengoku period, Satake Yoshinobu seized it after killing the local lords of Hitachi through a plot.

Curious to see what kind of castle had such a history, I came here to take a look for myself.

This is the parking lot at Shiroyama Park.

It is relatively spacious.

From the parking lot, we climb these stairs to head toward Kashima-jo.

The first set of stairs looks like this.

There is also a slope next to it, so you can choose whichever is easier to climb.

At the top of the first set of stairs,

there is a sign with arrows pointing the way.

To reach the Honmaru (本丸：main enclosure), head to the right.

The site where the Ninomaru (二の丸：second enclosure ) once stood is now occupied by a high school.

From there, we climb another steep set of stairs like this.

It is a typical hirayama castle（平山城）.

This is the summit area we reached.

It seems that this area was the site of the Honmaru (本丸：main enclosure).

It is said that Satake Yoshinobu, who had seized the castle from the Kashima clan through assassination, later found himself on the losing side at the Battle of Sekigahara.

He was ordered to transfer his domain to Akita, and in his place the former Kashima clan was appointed to an important position at Kashima Shrine.

From the site of the Honmaru (本丸：main enclosure),

you can see a large torii gate along the Kitaura lakeshore (the First Torii of Kashima Shrine, West Gate).

This photo was taken with significant zoom to make the torii easier to see.

In reality, it is much farther away.

The Honmaru Surrounded by Broad Earthen Ramparts

The torii seen from the top of Shiroyama is magnificent !✨✨

I spent a moment admiring the torii visible in the distance,

but then I began to look around to see if there were any other notable remains at the site of the honmaru.

Turning my back to the information board and looking around again,

there is a space large enough to make you think,

As expected, the site of the honmaru is quite spacious!

There were no information boards nearby,

so it may have been reconstructed (or newly developed) later.

However, broad earthen ramparts extended around the entire honmaru.

Please take a look at the scene in the video below.

Since it was a Sunday, many families with children from the neighborhood had come to play.

Castle ruins often end up becoming parks.

In any case, I think you can clearly see the shape of the Dorui（土塁：earthen ramparts）.

Dorui（土塁：earthen ramparts） look like this.

You can walk along the top of them normally,

and within the park they serve as a walking course.

While walking along, I also came across something that looked like a small shrine like this.

I discovered a fairly deep dry moat!

The earthen ramparts I found at the site of the honmaru continued all the way around the park,

so by walking along them, I ended up circling the entire honmaru.

As I kept observing the surroundings to see if there were any other notable remains,

I discovered another slope leading into the park.

On both sides of this slope, which cars can also pass through, were fairly deep dry moats.

Please take a look at the scene in the video below.

Wow, I almost overlooked it.

It is actually quite a deep dry moat.

Even at castle ruins that seem to have nothing left,
if you walk around searching carefully, you can often find something.

After circling the honmaru along the earthen ramparts and returning to the starting point,

I recorded another video.

It also captures the torii visible in the distance.

I couldn’t find any other remains that might be considered historical features,

so unfortunately, this is where the exploration ends.

However, before coming here I had expected there might be nothing more than an information board,

so discovering the earthen ramparts and the dry moat was already a worthwhile result.

The view from the top of the hill is not bad either,

so if you have a chance to visit the area, it’s definitely worth stopping by.

➡️ 『Castle Explorations』page