Recommend me J-techno.
 

Hehe yea, anyone?

Well, could you be a little more specific please? =) Do you mean like trance music, or just really good dance music? I'd be more help for the latter than the former.

i dunno if this is trance, but it is dance music. try out Nami Tamaki. she's got good dance songs. i don't specifically know if her music is trance, though.

Para Para groups might be good. Kingyo, Gyaruru or HINOI TEAM.

TRF. or perhaps Aural Vampire?

In terms of just really good dance music, I'd also recommend (old) dream and (old) MAX. :yes

capsule and Perfume are techno-ish.

Not really techno, but dance anyway. XDD I suggest Eri Nobuchika, MONDO GROSSO and Genki Rockets. :3

Yes, Eri Nobuchika is a must-try.
Lights and Yume no Kakera

Next, you should try Mai Kudou.
Reborn, Eyes, Princess Candy.

melody.'s Ready To Go album also have this techno-influences, as well as ERIKA's FANTASY song.

Mai, as Keishi pointed out, is well worth a shot. Also, melody.'s album opener, Finding My Way, is really dancey from the short snippet that I've heard.
And um... I've been seeding this J-techno album on JPS for months now, by this band called Floppy. :D I only listened to it once, but it was okay, I guess. More like electronica.

As dokidokisuru said, Perfume are definately worth a look at.

Some Songs

RAM RIDER - Smile Again
m-flo - Any of the m-flo loves series
melody. - Deja Vu
melody. - Dangerous
melody. - HOPE
melody. - Finding My Road
melody. - Shine
Mai - Princess Candy
Mai - Reborn
Mai - Eyes
Mai - Here We Go Again
Gyaruru - Boom Boom Meccha Maccho!
Kingyo - Lover's High
sifow - LOVE & PEACE
sifow - Carat
Perfume - Electro World
Perfume - Linear Motor Girl
Perfume - Chocolate Disco
Nami Tamaki - Get Wild
Nami Tamaki - Result
Nami Tamaki - Prayer
Ami Suzuki - Delightful
Ami Suzuki - Fantastic
Namie Amuro - Come
Nochiuri Natsumi - LOVE LIKE CRAZY (This is like the K-pop and C-pop..)
Elegies - Inshousha Renoir You Ni (I believe that's the name, but god it's addicting!)

and if you'd like some K-pop or C-pop... It's mostly R&B with lots of techno beats. lols.

Hyori Lee - Get Ya
se7en - Girl Friend
Hyori Lee - Shall We Dance? (feat. David)
Baby V.O.X. Re.V - Shee
Kelly Chen - Xinkou Buyi (You Don't Mean It)
Ivy - Temptation of Sonata feat. Wheesung

and then three other korean songs that I can't read the titles for. XD

Definitely with you on the Aural Vampire. They're great and just about the only J-Techno I listen to, unless you consider Tamaki Nami techno (which I don't think she is, more like dance/electro-pop).

i prefer dance tracks.

any uploads? :D