I just arrived here (tokyo) so I haven't had a chance to to explore the psy scene IRL. But at least on the net there doesnt seem to be too much of a lack of events listed. And though I don't speak japanese with the help of google translation, and babel fish together with some good old fashioned guessing I've managed to find and navigate quite a few japanese psy-trance sites. Here is a collection of the links i put together for my self. some of the sites are labels, others are stores or community sites. the general theme though is that they have psy-trance event listings for the japan (tokyo-based) scene. Give it a try, i'm pretty sure you'll find at least some of it understandable. once you find something you wanna go to in the worst case you can always ask a japanese friend or random person sitting next to you in a manga/internet cafe to help you order it real quick. I've noticed that some of the out-door events (mainly why i'm interested in) even organise accompanying bus rides from/to tokyo.
for example this evening i'm heading out on such a "Magic Bus Tour" from shinjuku to a 3 day party south of tokyo. (http://www.tirakita.com/event/) part psy-trance part more traditional indian music. Either way the party pics from 07 and 08 look great. tickets were limited to 400 people so it won't be one of those Mega-Events which i'm not all that into anymore. basically i've decided that unless the location is insanely awesome (like some of the solar-eclipse parties) or tons of my friends are going i usually end up having a better time at small more personal parties. that goes for European parties as well as US ones. And i gotta say, i kinda like the idea of trying to bring in some new elements into the traditional outdoor psy-trance events. Yeah it isn't EXACTLY the same kind of party we all grew to love 5-10 years ago, but hell, why NOT try something a bit different for once. :-)
Tokyo-based Psy-trance links
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6 dimension soundz
Blissdom
BrainBusters
Eclipse CD Shop
Fineplay
Music BBS
Fullmoon Records
Fullsmoke
LTS (down now, but was up just a couple weeks ago.)
Mother
NewWorld
SIRIUS RECORDS
Solstice Music
Sonic Traveler
Sunflowers of Today
T.P.E. RECORDS
Vision Quest
Yet more links for the Japanese psy-scene (Just found this randomly right now. Probably has a bit of overlap with the stuff above.