白金
Shirokane
(silver coins)

Shirokane appears in a few place names |
Shirokane |
Shirokanedai |
Shirokane-Takanawa |
Shiba-Shirokane (now defunct) |
So the story goes that in the 14th century, a powerful clan migrated here and took the area under their direct control and began the development and cultivation of the area. According to the legend, the family was called 柳下氏 Yanagishita or Yagishita or Yanashita the Yanagishita clan[i]. The story goes so far as to allege the head of the clan was a certain 柳下上総之介 Yanagishita Kazusanosuke[ii] who was so rich that he was called the 白金長者 shirokane chōja the silver coin millionaire[iii]. Bear in mind that there is very little corroborating evidence to support this story.
The name Shirokane first appeared in 1559, when the so-called Late Hōjō clan granted a place called 白金村 Shirokane Mura Shirokane Village to the great grandson of Ōta Dōkan. But the story I just told you doesn’t appear until the late Edo Period.

According to the experts, of which I ain’t one, judging from the topography there clearly was a pre-Azuchi-Momoyama fortress in the area[iv], which at least indicates that some powerful lord lived in the area before the coming of the Tokugawa. The ruins, which are just embankments and plateaux today, can be seen in Shirokanedai at the 国立自然教育園 Shizen Kyōikuen National Park for the Study of Nature. You can see their busted ass English website here. I haven’t been to this place myself, but it seems that the hills and ridgeways are the remains of the original earthen fortifications. This Japanese website goes into some detail on the topic.
Again, I’m not an expert on castles, but in the Kamakura Period, this area fell under the domain of the clans such as the Edo and the Shibuya. One of these clans may or may not have had fortresses in the area – and it’s possible that they could have – and the timing is right. Apart from the anecdotal story from the late Edo Period, the Yanagishita clan is otherwise unknown in the area.

Complicating the issue, later, after the coming of the Tokugawa and the establishment of 参勤交代 sankin-kōtai the alternate attendance system, this area became home to many palatial residences of 大名 daimyō lords. In 1627, the 讃岐高松藩松平家 Sanuki no Kuni Takamatsu-han no Matsudaira-ke the Matsudaira Family of theTakamatsu Domain in Sanuki Province, a branch family of the Tokugawa, established a 下屋敷 shimo-yashiki lower residence here. As mentioned in my article on sankin-kōtai, of a lord’s 3 usual residences, the lower residence was usually the grandest and would have included beautiful gardens and ponds.

(ie; the dude who had to surrender his bad ass mansion in Edo to the Meiji Government)
In the Meiji Era[v], the imperial government set about its wholesale erasing samurai history and appropriated the sprawling palace of the Matsudaira and repurposed the land as an arsenal for the Imperial Navy. In 1893, the arsenal was transferred to the Imperial Army. In 1917, the wooded area was granted to the Imperial Forestry Bureau. In 1949, the area was finally open to the public as 国立自然教育園 Kokuritsu Shizen Kyōikuen the National Park for the Study of Nature.
OK, so this is the traditional narrative and, as mentioned, etymologically speaking it’s open to a lot of criticism. That said, the presence of fortifications there are very real.
Alternate Etymology
However, another intriguing theory exists. This theory proposes that the name actually derives from a Classical Japanese phrase 城ヶ根 shiro ka ne/shiro ga ne/jō ga ne which would mean something along the lines of “the castle’s embankments” or “castle foundations.” According to this etymology, the presence of a former lord’s castle ruins from time immemorial came to be written in more auspicious kanji, ie; 白金 shirogane/shirokane “silver” or “silver coins.” In the Edo Period, a folk etymology came to be circulated which created this Shirokane Chōja Silver Coin Millionaire character and story.
This new theory simply re-spins the traditional narrative but it doesn’t seem so cheesy. It also falls into a pattern that we’ve seen with Kantō place names that pre-date the Edo Period. It doesn’t have widespread acceptance, but there are other place names around Japan that use the word 根 ne (literally root/source, specialized geographic meaning “ridge, embankment” in relation to a fortification). Actually, we’ve already seen a 根 ne conjecture in the etymology of Nerima.
The Verdict
Which is correct? I don’t know and we’ll probably never know. But that’s the thing with history, isn’t it? As much as we want a clear picture of what really happened, we’re always reaching.
Another kind of interesting thing about this place name is that it does mean “silver” or “silver coins” and to this day the area is located in the richest ward of Tokyo.
Oh, one last loose end to wrap up! So at the beginning of the article, I mentioned some other place names. The etymology of 芝 Shiba can be found here. The etymology of 高輪 Takanawa can be found here. 台 dai, on the other hand, needs a little explainin’.
The kanji 台 is a reference to a 台地 daichi plateau. As mentioned earlier, the area was clearly fortified no less than 500 years ago. The area was probably a naturally high area, but it was intentionally built up too. Anyways, while one common meaning of the kanji 台 in a place name is “high ground,” it’s not always a reference to elevation in the modern geological sense (think sea level); it was a much more relative term. But in this case, it is most certainly a reference to the foundations of the old fortifications.
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[i] The name itself is interesting, it means “under the willows,” but it has 3 possible readings. I’m not sure which the correct reading for this particular clan is as I’ve seen both Yanagishita and Yagishita in reference to this clan. Yanagishita seems to roll off the tongue a little easier, so I’m going with that one.
[ii] The traditional story also asserts that homeboy was a minor official in the service of the 南朝 Nanchō, the Southern Court. Readers unfamiliar with the establishment of the Muromachi shōgunate should know that in the 14th century, there was a succession dispute in the Imperial Family which led to the establishment of a second Imperial Court. Long story short, the Northern Court won and the current imperial line claims descent from this branch and considers the Southern Court a bunch of poseurs. Read more about the Northern and Southern Courts here.
[iii] Silver coins or silver itself, usually 銀 gin in modern Japanese, were apparently called 白金 shirokane at the time. Technically speaking, both methods of writing can be read as either gin or shirokane. There is an additional reading hakkin which means platinum.
[iv] If you remember from my article on What does Edo mean?, when you think “Japanese Castle,” you are most likely thinking of structures that were first developed around the time of Oda Nobunaga and reached their peak of development in the Edo Period. But the word 城 shiro is applied to both structures.
[v] In 1871 no less. This is so soon after the 1868 Meiji Restoration, that it seems like a deliberate dig at the Tokugawa to me.