練馬
Nerima

(original meaning unclear)

Today’s place name is another request. It was on my TO DO list but I sorta put it off because… well, let’s just say “can of worms.”

The history of Tōkyō generally starts with the Edo Period. But it wasn’t like this city just popped into existence in 1600. Before Tokugawa Ieyasu, there was Ōta Dōkan. Before him there was the 豊島氏 Toshima-shi Toshima Clan* and (spoiler alert) the Edo Clan. In terms of written records and political relevance, this area’s history actually begins in the Kamakura Period and only accelerates from there.

Background Info

The Toshima clan controlled large areas of 武蔵国 Musashi no kuni Musashi Province. Most of their dominion fell within the present Tōkyō/Chiba area. The 郡 gun district was called 豊島郡 Toshima-gun. Their seat of governance was in at 平塚城 Hiratsuka-jō (also known as 豊島城 Toshima-jō), but the family was firmly established in their residential estate in Shakujii Castle and had another fortification at Nerima Castle).** Today in Kita Ward, there is still a shrine called 平塚神社 Hiratsuka Jinja Hiratsuka Shrine. So the Toshima influence was strongest in the north region of Tōkyō. Place names that will definitely come up later will be Itabashi and Edo. The only reason I mention this is because these names will come up again later, for sure.

But OK, back to the subject at hand…

What does Nerima mean?

At first glance the kanji are confusing.

練 neri training, kneading
馬 (u)ma horse

First, let’s look at the etymologies that make use of the 練り neri “training” and 馬 ma “horse” theories

★　One of the oldest stories, documented from the Kamakura Period says that sometime between 700 and 800, there was a road connecting 武蔵国 Mushashi no Kuni Musashi Provice and 下総国 Shimōsa no kuni Shimōsa Province. On that road the Toshima clan had a 宿駅 shukueki a horse relay station. The name of the relay town was 乗沼 Norinuma, “ride-swamp”. This etymology claims that because the area was a wetland it had many lakes and, well, you could refresh your horses there, too. The local accent changed “Norinuma” to “Nerima” and eventually the kanji was changed to ateji.

★　Another theory says vassals of the Toshima family were training horses here. This is the most believable story, though it isn’t attested as early as the previous theory. So the name “training horses” is literal.
Compare this to Takadanobaba.

★　Another literal theory says some dude was stealing horses and keeping them here and then training them for resale. This kind of etymology, while entertaining, is unlikely IMO. But who knows…

Now let’s look at the clay theories

★　Another theory uses an alternate meaning of the kanji 練 neri. The kanji can also mean “knead” as in “knead bread” or “knead clay.” Supposedly there was an abundance of great clay for pottery making and the place was famous for kneading clay. This etymology says the name was originally 練場 Neriba Kneading Place. There are many examples of diachronic changes and dialect variants where ば ba becomes ま ma (and vice-versa). So linguistically speaking, it’s not impossible. On the site of the former Nerima Village (present day 貫井 Nukui), archaeologists discovered a type of kiln which was rare in the Edo-Tōkyō area.

★　Another clay theory claims that the dirt and clay in the area was sticky as if it had been kneaded professionally. Thus the area was called 練場 Neriba, just as in the theory I just mentioned. Over time the pronunciation changed from Neriba to Nerima. The clay hypotheses are intriguing.

★　I’ve saved the weirdest theory for last. The Shakujii Basin lowlands were an expanse of lakes and swamps and so if you looked at water filled rice-paddies they looked really deep, as in “deep to the roots.” 根 ne root + 沼 numa swamp, marsh = 根の沼 Ne no numa root deep swamp, which changed to 根沼 Nenuma root swamp. Eventually Nenuma changed to Nerima and the kanji was changed to ateji (just like Hibiya).

BTW – The place name 丹根沼 Tannenuma exists in Hokkaidō.

So it looks like the jury is out on this one. And while every theory, except the last one, has an argument based on kanji, the possibility of the name being just ateji is very possible. It’s particularly possible with old names that pre-date the Edo Period. At any point in history ateji could have been used – and changed later again to support other folk etymologies. So this one will just be a mystery.

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* Toshima can be written 豊島 or 豊嶋.
** Toshima Amusement Park (called としまえん Toshima-en in Japanese) is built on the castle ruins of Nerima-jō.