Actually, .jp is popular in Japan (of course), but using an "S" on a noun reduces the value dramatically in Japan. The common 40-80year old company owner doesnt know how to use the plural form of nouns.
- As English speakers, we simply say and spell it as "groups"
- in Japan, they say it as "guruupusu" and spell it as "gloupsu".
- In Japan they use "katakana" for any non-japanese words.
- in using it as a domain name, they prefer singular.
- In Japan, hyphens "-" have higher value than "noun+S"
- There are plenty of "noun+S" .jp domains available.
Im so sorry to say, but the value is exactly what you paid for.
My advice for you is to study the language before you start investing in Japanese domain names. If it were a .com, then i think you would be rich.