Yakami Castle

The trail up to Yakami Castle is well maintained, with clear signage marking all the major baileys. However, the kyokan area at the base of the mountain deserves more attention. There are multiple baileys and interesting earthworks you can discover by straying from the main path, and scrambling over

History

The Hatano clan, originally from Iwami Province, rose to prominence after aligning with Hosokawa Masamoto during the Ōnin War. Following the conflict, they were granted territory in central Tanba and established a power base at Yakami Castle — a formidable mountaintop overlooking the fertile plain of what is now Tanba-Sasayama. Strategically positioned at a chokepoint on one of the main roads into Kyoto, the site later drew the attention of the Tokugawa Bakufu, which built nearby Sasayama as one of its key Tenkabushin (天下普請) castles to control Western Japan.

By the mid-1500s, the Hatano had consolidated control over much of the Tanba highlands and the Sasayama plain. They emerged as one of the region’s most powerful Sengoku-period daimyō, but their resistance to Oda Nobunaga’s authority placed them directly in his path during his western campaigns. In 1575, Nobunaga ordered Akechi Mitsuhide to subjugate Tanba. Mitsuhide’s initial attempt faltered at Yakami Castle and Kuroi Castle due to difficult terrain, local uprisings, and overextended supply lines.

In February 1578, renewed resistance flared across Tanba. Nobunaga again dispatched Mitsuhide, this time with orders to crush the Hatano clan entirely. Mitsuhide laid siege to Yakami Castle in March, cutting off supplies and waiting the defenders out. Over the course of a grueling year-long siege, it is said that more than 500 samurai perished from starvation. Eventually, a traitor from within the castle opened negotiations with Mitsuhide, leading to the Hatano’s surrender on the condition that the Hatano brothers were not harmed.

Mitsuhide, honoring his promise, escorted the Hatano to Azuchi Castle under assurances of clemency. However, Nobunaga — perhaps viewing the Hatano as a lingering threat — ordered their execution in Kyoto. This perceived betrayal by Nobunaga is frequently cited as one of the grievances that later motivated Mitsuhide’s own betrayal at Honnō-ji in 1582.

A local legend adds further drama to this episode, claiming that Hatano retainers, in revenge, captured Mitsuhide’s mother (said to have been nearby) and executed her. While this tale lacks any historical evidence, it reflects the bitterness surrounding the fall of Yakami Castle.

The kyokan area at the foot of Yakami Castle remained in use until around 1609, when the Tokugawa government constructed Sasayama Castle approximately 4 kilometers away as part of its broader efforts to pacify and control western Japan.

Field Notes

The trail up to Yakami Castle is well maintained, with clear signage marking all the major baileys. However, the kyokan area at the base of the mountain deserves more attention. There are multiple baileys and interesting earthworks you can discover by straying from the main path, and scrambling over fallen trees and bamboo. Given the size and importance of this residential compound, a little more signage or maintenance would greatly enhance the experience of this valuable site.

Around the mountaintop baileys, there was once extensive stonework. Some sections have collapsed over time, and much of it is now hidden under thick vegetation. I’ve heard from senpai castle explorers that the stonework used to be much more visible before the surrounding trees were cleared and tall weeds and thick vegetation grew up in their place. They've cut some paths through the weedy areas, but a little more maintenance could dramatically improve the site’s impact. I would happily volunteer a weekend to help!

The Sasayama valley once supported a dense network of satellite castles centered around Yakami Castle. From the mountaintop, you can spot small "islands" scattered across the valley. These are small hills and mountains, most of which once held fortifications. The surrounding region also hosted a wider web of fortresses controlled by Hatano allies. Unfortunately, most of these sites are unmaintained, overgrown, or located on private property. With limited public transportation, they remain difficult to access — but I hope to explore more of them someday.

Yakami Castle had been on my list for many years after a strong recommendation from Shiro Megumi Fan during one of my early visits to the area. Until recently, though, it was somewhat difficult to reach. The main options were cycling 7.5 km from Sasayamaguchi Station, or taking a bus to downtown Sasayama Castle and walking 4 km to the trailhead — not ideal in such a castle-rich area where time is precious. There are a few infrequent local buses that stop closer, but poor scheduling means you’ll end up waiting a long time or walking back anyway.

Since bicycle rentals began at the Sasayama Castle tourist information center, the 4 km ride to the trailhead has become a practical and enjoyable option. This made it possible for me to comfortably visit Yakami Castle, nearby Okudani Castle, Hannyaji Castle, and still swing back for a quick revisit to Sasayama Castle before dark.

As of November 2024, the lower section of the eastern trail is partially closed near the base due to a landslide or washout. After exploring the castle ruins partway down this ridge, I had to retrace my steps back along the same route, but that did give me a new chance to take photos from the top under sunnier conditions than the dark cloudy ones earlier in the morning. You may want to check the signs I ignored at the top of the site or ask if the trails are all clear at the information center.

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Gallery

part of an original chaya nearby

Castle Profile
English Name	Yakami Castle
Japanese Name	八上城
Alternate Names	Yakamitakashiro-jo, Takashiroyama-jo
Founder	Hatano
Year Founded	late 1400's
Castle Type	Mountaintop
Castle Condition	Ruins only
Designations	National Historic Site
Historical Period	Pre Edo Period
Features	trenches, stone walls
Visitor Information
Access	Sasayamaguchi Station, bus
Hours	Mountain trails, open any time
Time Required	150 mins
URL	Castle Website
Hiking Trail	View on Yamap
Location	Tanba Sasayama, Hyogo Prefecture
Coordinates	35.06185, 135.25614
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Admin
Added to Jcastle	2025
Contributor	Eric
Admin Year Visited	2024
Admin Visits	November 7, 2024
Friends of JCastle
Kojodan
Shirobito
Shiro Meguri Fan

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