kouta or kota?

Hi,
Well, I'm a little bit confused about how to write some Japanese first names in English, and I'm talking about names that have a long vowel sound in them. For example, I would write :
ゆうた　こうた　しゅうや　りょうたろう
Yuuta Kouta Shuuya Ryoutarou

I wouldn't write:
Yuta Kota Shuya Ryotaro

(you could write it the way above if you included the line above the long vowel sound).

But, today one student queried me on this and so I was wondering if I have been doing the right thing. Let's say his name is こうた . I would spell this out "Kouta", but he says it's "Kota".
He's not being difficult or awkward, he's just a kid who's confused because he's been taught until now to write his name "Kota" and then I come along and tell him "Kouta".

The two sounds are very different: こうた would be pronounced "Ko u ta" and "ko ta" sounding like "cotta" as in terracotta which isn't right.

So, which is, Kouta or Kota? Yuuta or Yuta?

To tell the truth, there are some ways to spell it.

Recently I often spell "Kouta" that is the same as Hiragana spelling こうた.
But "Kōta" and "Kôta" are the same as pronunciation コータ.
And also "Kohta" and "Koota" are the same.
(The latter "Koota" is very rarely used.)
Some think "Kota" is more Englishlike spelling, it's often happened to see,
but in this case, it's hard to tell the difference between こうた and こた.

Now, are there 6 ways to spell こうた, I think?
To begin with, Japanese language is not written in the alphabet,
so all of them is not misspelling...

How are Tokyo, Kyoto, etc. commonly spelled & pronounced?

@orange pen

The most accurate way of romanizing it would be to use a macron (bar) over the "o", but as many keyboards - especially smartphones - don't support macrons easily, it's easier to leave it out. You may see people use "ou" or "oh" to represent the long "o" sounds occasionally, but that's non-standard, and for your interest, the official government guidelines on how names are romanized in Japanese passports explicitly stipulate that long vowels must be represented by a single vowel (i.e. Kota, Yutaro, etc). In other words, he's right, and you're wrong. (grin)

For names that might be true (if it's stated they must be written with only one vowel in the passports), but for places it's not a standard. I've seen places written with two "o" and only one.

Strictly speaking, there are various ways to "romanize" Japanese. Some people will write "Kyusyu" instead of "Kyushu", and both are correct. This is confusing for foreigners. The same happens with "Kouta" and "Kota". If he says and has been taught that he must write his name with one vowel, then that's the correct one (even that you're not mistaken). However, it would be good to teach the kid that his name may be pronounced incorrectly by a foreigner if he/she sees it written like that.

Thanks to everyone who replied to my question.
So it would seem both Kouta and Kota are correct, but Kota would be the version used for passports.