Etymology of Yama-Arashi?

Question

Most¹ Kodokan judo techniques are named in a somewhat systematised way, describing the major visual/mechanical components of the technique (e.g. koshi-guruma "hip wheel", o-soto-gari "major outer reap"). This is in contrast to the various impressionistic names of apocryphal techniques (e.g. jigoku-jime, chōchin-datami, tama-guruma).³

Yama-arashi (山嵐, "mountain storm") then seems something of an obtuse anomaly in the Kodokan syllabus.²

What is the etymology behind Yama-arashi?

Does it have anything to do with porcupines (also called yama-arashi, ヤマアラシ, 山荒 in Japanese)?

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<sup>1. There are other more metaphorical, yet still penetrable, names: tawara-gaeshi, tomoe-nage, kani-basami, tani-otoshi, kesa-gatame.
2. Along with a couple of others: tsubame-gaeshi, kawazu-gake.
3. With some being named for famous practitioners: tengu-nage, nanma-otoshi</sup>

Answer 1

Yama-otoshi → Yama-arashi

Yama-arashi derives from an earlier jūjutsu throw yama-otoshi:

Yama-arashi is recorded in Sekiguchi-ryu (the old style of jujutsu) as yama-otoshi.

• Kodokan Judo Throwing Techniques (p.78)

Thus it seems to have had an etymology similar to tani-otoshi originally, and given some added 'flair' at some point during its adoption into the go-kyo.

Porcupines

Though the Japanese word for porcupine predates the judo throw by around two centuries,¹ the word was fairly obscure and (though pronounced the same) uses a different character for arashi,² hence the similarity is likely coincidental.

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<sup>1. Japandemonium Illustrated: The Yokai Encyclopedias of Toriyama Sekien (p.298)
2. Although 嵐 is indeed hypothesised to derive from 荒らし etymologically.</sup>