I have never seen the Japanese yen symbol written with just one bar. But I happen to know that the Latinized symbol for the Chinese renminbi, which is theoretically identical to the Japanese yen symbol (it shares the same Unicode code point), is more frequently written as a Y with a single crossbar. So you want to watch the context.
A similar letter apparently appears in Kazakh Cyrillic.
As for the Euro symbol, I doubt it would be recognizable with just one bar--it would look too much like the Ukrainian Ye to me in any event.
I've seen plenty of fonts with a single-bar yen. I don't know the formal rule however. I'm doing a font right now with one. The euro is certainly a little odd with only one however, and I'm sure I've seen certain rules issued in the early days of its existence with regards to the angular chops off the end -- though this of course is open to experiment and evolution like any other character. A double bar yen would therefore seem to fit visually with this and the rest of the currency (double bar $ anyone?)
I used to double bar the $ in handwriting all the time! Probably influenced by the Korean and Japanese practice of using a Chinese character that looks like a flipped double-bar $ as the dollar sign...
And to clarify, I certainly have seen single-bar Ys, but I don't remember ever seeing one that was meant to be the symbol for the Japanese Yen as opposed to the Chinese Renminbi.
for the Euro, although anything goes from what I've seen, but nearly always double bar.
http://en.wikipedia.org/wiki/Image:EuroConstLarge.png
Tim
> nearly always double bar.
And sometimes an eye:
http://www.myfonts.com/fonts/microsoft/comic-sans/ms/win-ttf/1157/charac...
hhp
The new euro symbol was officially presented as “an epsilon harking back to the cradle of European civilisation and the first letter of Europe, crossed by two parallel lines to indicate the stability of the euro.” But according to Mr Eisenmenger, the symbol was drawn “without much consideration” for some temporary purpose, and was not at all intended as a currency symbol.
Quote from Hrant's link, the eye is dotted and the euro crossed (twice).
Tim
The Euro was first build in 1974 to become a logo for the European Parlament. They didn't want the proposal and archived it. When the idea came up to produce a pan-European currency they remind of the proposal by Arthur Eisenmenger, took the logo and used it as the character for the Euro.
Guide for a correct Euro-Sign:

1. affinity with the other currency signs
2. a little bit smaller and thinner than capitals
3. resemble more a lowercase c than an uppercase C
4. demands the same room as the numerics
5. crosses have sufficient distance
6. contrast, greytone, serifs… like in the main font
more about it: http://www.hitext.de/euro/euro.html (german)
Greetings: Steven
I'm fond of the Pillars of Hercules explanation for the double bar dollar:
http://en.wikipedia.org/wiki/Dollar_sign
where it's argued that the sign is derived from a Spanish crest showing two pillars wrapped with a ribbon bearing the words "Plus Ultra".
And to confuse things further here's a SINGLE pillar with the ribbon on a version of the crest:
http://www.vivagranada.com/alhambra/mexuar.htm
Second image down...
> Yeah, but you guys put a bar on our “D”, and we don’t. :-)
Some of Japanese people used to put a bar on the stem of "D "(just like Eth) to distinguish the "O".
> Doesn’t Japanese have its own Yen Symbol anyway that precludes the need for the barred-Y that we use in the west?
> And this one with two:
Yes, As we always use the Yen Symbol with double bars, It is familiar with us than the Yen Symbol of Angie Sans.
> ... to distinguish the “O”.
Yes, alphabet reform! The same happened to the "7" in Europe. Don't get me wrong, I think it's a great idea. And people whose native script is Latin shouldn't be angry that a non-native is messing with his writing system; but by the same token, the single-bar Yen might be an even better idea.
hhp
Captured from commoncrawl.org on 25 Apr 2015. original URL