Well, the renewal fee for my bankruptcy.jp domain is $100 a year, so for those thinking about investing in a domain for resale later that must be considered. If you know Japanese, then I think it would give you an advantage, since you really need to know the language and the culture to find a good domain to invest in.
I bought mine more for parking revenue than as an investment. I may be able to find a buyer or I may not. But even if I find a buyer I may not make much profit. In my case the Japanese word for "bankruptcy" is something very different. While most Japanese know quite a bit of English they are not likely to use the English word unless then are located in a country where English is the main language.
I see very, very few Japanese domains here at NamePros, so my feeling is that the Japanese domain market, at least for Romanji (English) character domains is not bery active.
I do have to add that if you have ever been to Japan you will notice that they use English words much more often on buildings, signs, and even TV ads then we use Japanese words here in the US.
If I can add my 2 cents, the Japanese are not at all into domaining at this point. There are a few domains offered at Yahoo auctions (No ebay in JP), but the prices asked are absurd, and the bids are non-existent. At $100 a year for renewal it had better be a fantastic name. I talked to the guy who owned harajuku.com, and he hadn't even parked it. He was just sitting on it for development "someday."
On the other hand, Japanese housewives have gone mad for the forex market. If they ever get wind of domaining, watch out.
MIR is right. You could reg a dozen dotcoms the price of one dotjp - much more chance of seeing profit there.
Im with MIR on this one. I am a firm believer that your better off investing in a good .com or .net rather than putting your money into something like .jp or .asia. just
I just checked my one .jp domain and so far this year it has made about $32 from parking. At this rate I will be earning just about enough to pay for the renewal when it comes due. So if you can find a good domain that will at least pay for itself and that has the potential to someday have resale value, then it may be worth investing in them.
Otherwise I have to agree to do with the more popular TLDs, or any that are under $20 a year. to register.
JP domain 
