In the midst of the ongoing SARS-CoV-2 pandemic, Twitter user @talkporty* got in touch to ask:
Dear @shadychars, you are the only one I can turn to in this situation. I am being hounded by EM-DASHES! Help! How has #covidー19uk become a trending hashtag? Nobody types them in.
And crazier still: paste it in and it seems it is [the] chōonpu symbol instead!1
It isn’t often that international health crises and punctuation intersect, but these are the times in which we find ourselves.
First things first: I tapped on the #covidー19uk hashtag to discover that is indeed it a valid hashtag, and also that a lot of people are using it. Next, I did some copy-and-pasting of my own to confirm that “ー”, a character that looks very much an em dash, is not, in fact, an em dash. As @TalkPorty said, it is the chōonpu — AKA the “long sound symbol”,2 AKA Unicode’s KATAKANA-HIRAGANA PROLONGED SOUND MARK3 — a dash-like mark used to indicate long vowels in Japan’s katakana and hiragana syllabaries.
How did a dash-like non-dash end up in one of the most common hashtags at a time of global crisis?
At first, I assumed that it must have been a cut-and-paste error. As @TalkPorty suggested, rare is the person who knows how to enter an em dash on the computer’s keyboard, and I wondered if the hashtag’s original creator had perhaps browsed a list of Unicode characters until they found a likely-looking candidate. But that didn’t seem entirely plausible: you have to stray pretty far from Unicode’s Latin alphabet and its accompanying marks before you reach katakana and its punctuation. The idea that this was accidental, or coincidental, didn’t quite fit.
Next, I wondered if it could have been a typo caused by a smartphone’s software keyboard. Perhaps a Twitter user hunting for an em dash alighted on a visually similar mark by mistake. Probably not, I thought, for the same reason as before: if you have your phone set to display a QWERTY keyboard for a Western alphabet, you almost certainly won’t have ready access to the chōonpu. It takes a deliberate effort to switch languages and go hunting to find one.
In summary, someone must have chosen this character deliberately, though I was none the wiser as to why they had done so. In the end, I blundered into what I thought was a plausible solution. Here are my original tweeted replies to @TalkPorty:
Well, that’s weird. I can only imagine that some cut-and-paste or soft keyboard error has gone viral (sorry) along with the hashtag.
If I tap on the hashtag in Twitter’s Android app, I’m given the option to compose a tweet containing that same hashtag. I’d imagine that’s how it’s spreading. #covid-19uk (with a hyphen-minus) is also doing fairly well.
Wait! I lie. #covid-19uk isn’t a valid hashtag! Presumably someone has figured out that KATAKANA-HIRAGANA PROLONGED SOUND MARK can be used to “hyphenate” rather than break apart a hashtag. Very clever.
In other words, it seemed very much as if some savvy tweeter had used the chōonpu — a character that looks like a dash but works more like a letter — to construct a hyphenated term that sneaked past Twitter’s rules for valid hashtags. I left it at that.
As I was writing this post, though, I couldn’t help but wonder why the chōonpu in particular had been used. I’m not a Unicode expert, but it seemed unlikely that there was only one dash-like character among its 143,000 code points that could have been used to pull off this piece of hashtag hacking. Why did this Japanese mark end up in a hashtag otherwise comprised of Latin characters?

Now, some Japanese computer keyboards have a QWERTY layout, where roman letters are mapped to Japanese symbols in a system called romaji, and so, out of curiosity, I installed Google’s Japanese keyboard4 on my Android phone and took a look at its romaji mode. Right there, beside the ‘L’, was a chōonpu. Could #covidー19uk have been created by a native Japanese speaker with access to a romaji keyboard?
To find out, I used the Who Tweeted it First search engine to search for both #covidー19uk and #covidー19. The latter turned up the earliest tweet by over a fortnight, posted on the 11th of February:
なるほど、翌年のバージョンアップ(変異)にも対応できるのですね。
病名に続きそうな名前つけてしまうなんて、こういうのは普通なの?
#コロナウイルス
#COVIDー195
Well, what do you know? The earliest tweet to use the chōonpu in a #covidー19 hashtag was posted by a Japanese speaker with the Twitter username @spreadnewsxxx. Google’s mostly intelligible translation is as follows:
Indeed, it can handle version upgrades (mutations) the following year. Is it normal to give a name that seems to follow the disease name?
#コロナウイルス
#COVIDー19
Twitter reports that @spreadnewsxxx posted their tweet with an iPhone, whose Japanese keyboard I’m not familiar with, and so I can’t know whether they used the chōonpu for convenience or for its aforementioned hashtag friendliness. Either way, we now have a Patient Zero, if you’ll forgive the expression, in the form of the first use of the hashtag that has been plaguing @TalkPorty. The mystery is solved, or at least diminished.
I’d love to know if any readers have encountered the chōonpu in non-Japanese texts. Is this a common usage? Are its Twitter-defying powers commonly known? Drop me a line in the comments below!
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Wiktionary. “ー”.
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FileFormat.info. “Unicode Character ’KATAKANA-HIRAGANA PROLONGED SOUND MARK’ (U+30FC).”
- 4.
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“Google Japanese Input”. Google Play.
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- *
- For the curious, Talk Porty is a community discussion forum based in Portobello, a suburb of my old home town of Edinburgh. ↢