engineering

Sagiyama Castle

Sagiyama Castle is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Sagiyama Castle rather than just read about it. In short: Sagiyama Castle (鷺山城, Sagiyama-jō) was a castle built in Mino Province in middle Japan during the late-Heian period (late 12th century); it was destroyed during the Sengoku period in the mid-16th century. The castle's ruins are located in the present-day city of Gifu, Gifu Prefecture.

Key takeaways

Sagiyama Castle belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Sagiyama Castle to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Sagiyama Castle from memory before moving on to harder problems.

Reference excerpt

Sagiyama Castle (鷺山城, Sagiyama-jō) was a castle built in Mino Province in middle Japan during the late-Heian period (late 12th century); it was destroyed during the Sengoku period in the mid-16th century. The castle's ruins are located in the present-day city of Gifu, Gifu Prefecture. It stood at the peak of Mount Sagi, which was only 68 m (223 ft). Because the castle was built as a residence and not a defensive fortress, its location on a small mountain was of little consequence.

History Sagiyama Castle was built by Satake Hideyoshi between 1185 and 1190. It served as a main castle for the Toki clan, who were the shugo of Mino Province at the time, at first. However, after the construction of Kawate Castle to the south in 1353, Sagiyama Castle no longer played an important role in the area. Toki Yorinari moved into the castle in the early 16th century, but chose to live in Kawate Castle after becoming the shugo. After Saitō Dōsan usurped power from the Toki clan in 1530, he moved the area's power into Inabayama Castle atop Mount Kinka. However, he occasionally took refuge in Sagiyama Castle because of its ease of access. Dōsan gave possession of Sagiyama Castle to his son, Saitō Yoshitatsu, in 1548 after some repairs. Originally, Dōsan was planning on naming Yoshitatsu as his successor, but when Yoshitatsu heard that Dōsan might choose another son, Yoshitatsu killed his two brothers. The murders led to the Battle of Nagaragawa between Dōsan and Yoshitatsu in 1556, which resulted in Dōsan's death and the destruction of the castle.

Present In the modern era the site of Sagiyama Castle is preserved as a historic park, and a number of its earthworks — including low earthen ramparts and traces of moats — remain visible on Mount Sagi (鷺山). 岐阜の旅ガイド攻城団 In 1964, during large civil-engineering projects for the opening of the Tōkaidō Shinkansen and the construction of the Meishin (名神) Expressway, portions of Mount Sagi were quarried for fill material; this work reduced the size of the hill. During those excavations, workers recovered stones that have been interpreted as foundation stones (礎石) thought to be associated with the former castle structures. mori70shiro.dousetsu.com 歴史探索 Although parts of the mountain were cut away, the remaining castle site is protected and interpreted locally: a stone marker (城址碑) stands near the summit and the area is managed as Sagiyama Park, where visitors can still see sections of the surviving embankments and moats. 岐阜の旅ガイド登山とアウトドアの情報サイト／▴ヤマニア.net

References

Illustrations

Worked examples

Example 1 — a first encounter with Sagiyama Castle

Start with the simplest possible case. Write down what Sagiyama Castle claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Sagiyama Castle before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Sagiyama Castle ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Sagiyama Castle

In research: Sagiyama Castle appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Sagiyama Castle in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Sagiyama Castle is common in secondary-school and first-year university syllabi. It links to neighbouring topics Buildings and structures completed in 1190, Buildings and structures in Gifu, Castles in Gifu Prefecture, so understanding it makes those chapters shorter.
In everyday life: Look for Sagiyama Castle outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Sagiyama Castle in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Sagiyama Castle means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Sagiyama Castle out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sagiyama Castle in simple terms?

Why does Sagiyama Castle matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Sagiyama Castle?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Sagiyama Castle.