Sano Castle (Azumi)

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AzumiSanojou (1).JPG


I pondered the mysteries of Sanojō. The depressed area with parallel ridges is thought to have been the site of huts for shelter, and Ranmaru says this was 'to protect weak-legged women and children from the harsh wind and rain'. It is also speculated water may have been collected here. The elevation, at around 1,200m above sea level, and of a relative height of 450m, is considerable. At this height it is cold; heavy snow which does not melt for many months is guaranteed in winter, reducing the attraction of a place to hide-out. Cloud cover is considerable, lessening the utility of a smoke signal tower. The fortifications are significant, but why at such elevation? The fort was built to withstand a large attack from all sides from numerically superior forces. Yet who built it is unknown. The most likely explanation is that it was built under the orders of the Nishina Clan, mustering labour from throughout their domain, in the expectation of invasion by forces from beyond the province.

Visit Notes

Sanojō is a yamajiro (mountaintop castle) ruin in the Kamishiro area of Hakuba Municipality, North Azumi County. Ruins feature earthworks such as baileys, trenches and earthen ramparts.

In order to reach Sanojō I cycled up a forest road with many hairpins near the Sanozaka Ski Slope. Before that road turns across a gorge there is an even more dubious track going off to the north. I followed this path, now overgrown and unusable due to trees, and met at a bend with the ridge which would take me to the yamajiro site.

There was no trail and the going was steep. It had rained that morning too, and so there were slippy sections. I crawled up that mountain and later I slid back down! Skinny trees with flexible branches were a pain, as they tried to gouge my eyes when I approached, and whip me viciously as I went by, lashing at my lips and flicking my earlobes. I kept close to the earth to avoid falling down or over the ridge. Coming down I just slid, getting very dirty, and karate blocked the whipping trees.

Visiting Sanojō itself was very rewarding and interesting. The climb had made me work for it, but the nawabari (layout) also proved very fascinating, and there were some impressive ruins in the form of earthworks. The castle precincts span a section of the ridge which climbs for about 200m. There is a lower section which is very small but contains terraces on either side of a moat trace, though these earthworks are by now very deformed and only a maniac would suspect them. Climbing from the abandoned forestry road to these outer ruins was not easy and was at least a half hour slog.

A determined soul is rewarded when the castle ruins proper come into view. The ridge is carved with earthworks to create fortifiable spaces. There is a double trench complex at the start of the castle proper. Embankments and trenches create a wavy, undulating terrain. The double lower trench is followed by a middle trench and upper trench which protect terraced baileys. Between the lower trenches and middle trench is a confusing array of small terraced mini-baileys.

The fort's main bailey area is found between the middle and upper trench. This area is very interesting and I don't recall seeing its like before. The largest bailey, which I took for the main bailey, is to the right (going up), and there is a second bailey cluster (terraced), running parallel to it with a terraced depressed area in between. This twin bailey running parallel to the main bailey is novel. What was the sunken area used for? Indeed, the purpose of the fort in its entirety may only be speculated at.

I clambered up the second twin bailey and then up along the upper trench. The upper trench is the deepest, most impressive trench at this site. It turns out, however, that there are several upper trenches. Since Sanojō is built along the ridge rather than at a mountain peak, its defenders were concerned with rear defence especially, but it's amazing to imagine any signifcant force coming from the top of the mountain when the fort itself was already so high up. And the ridge which continues ever higher is even steeper and more unforgiving than that which drops below. But, of course, there being yet more fortification remains up here, I just had to keep on climbing.

I made it to the middle of the upper trenches, indicated by blogger and Shinshū yamajiro legend Ranmaru. I had come via the side a little and so I could already see, however, that there was yet another trench above this. So I climbed even more. Finally I made it to the upper of the upper trenches. This trench is the highest up but also the shallowest. Nonetheless, I was very happy to have made it to this highest goal. Sometimes one does not appreciate, however, how steep and dangerous a section of ridge is until one must go back down...

To make it to this furthest part of Sanojō is challenging and not without risk. I slid back down a game trail through a beast-sized tunnel hollowed out between the small trees. Only then did I enter the main bailey from behind via the (lowest) upper trench. The earth used to dig the horikiri is heaped up into a solid dorui (earthen rampart) segment at the rear of the main bailey. The views from here would've been amazing if not for all the trees!

  • Castle Mount
  • Horikiri

Castle Profile
English Name Sano Castle (Azumi)
Japanese Name 安曇佐野城
Founder Nishina Clan (probably)
Year Founded Sengoku Period
Castle Type Mountaintop
Castle Condition Ruins only
Historical Period Pre Edo Period
Artifacts Horikiri, Kuruwa, Dorui, Koguchi, &c.
Features trenches
Visitor Information
Access Minami-Kamishiro Station on the Ôito Line; 15 minute walk to trailhead
Visitor Information 24/7 free; mountain
Time Required 80 minutes
Location Hakuba, Nagano Prefecture
Coordinates 36° 37' 52.68" N, 137° 49' 51.60" E
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Added to Jcastle 2022
Contributor ART
Admin Year Visited Viewer Contributed
Friends of JCastle
Jōkaku Hōrōki
Shiro to Kosenjō

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