IDN domains

Internationalized Domain Names (IDN) are domain names that include local language characters, like those found in Chinese, Japanese, German, French etc.

Technically, the “special” characters (non US-ASCII) are encoded using the Unicode standard via a conversion table, and are represented in punycode.

This is why an IDN domain name will begin with the four characters xn––, and why you can’t otherwise register domain names with hyphens in the third and fourth position.