What Japanese bands/singers have you seen live?

I saw Kiyoharu at his year end 9 hour long concert in Osaka on Dec 2013. I don't mind seeing him again though.

Last year I saw Kalafina and they were absolutely stunning!

ONE OK ROCK~ when they came over to my country (Malaysia) last year.. hope to see them again and KAT-TUN one day..

I got to see Kotoko live last month. :) She gave an amazing performance.

I've seen quite some :D Most of them in Japan

THE MICRO HEAD 4N'S
堂本剛
L'Arc~en~Ciel
堂本光一
KAT-TUN
葵＆涼平
ユナイト
FEST VAINQUEUR
defspiral
Royz
ν[NEU]
ベルベット
ギルド
ケミカルピクチャーズ
R指定
愛狂います。
ドレミ團
Administrator
vistlip
KinKi Kids
Make
MiU
Synk;yet-シンクイェット-
DROSERA OBLAAT
THE SOUND BEE HD
Nocturnal Bloodlust
BLOOD
Suicide Ali
Miyavi

I've seen a lot of Japanese bands live. 
Melt-Banana - 3 times
打首獄門同好会 (Uchikubigokumondoukoukai) - 2 times
大森靖子 (Oomori Seiko) - 2 times
パイプカットマミヰズ (Pipecut Mummies) - 2 times

Other Japanese bands I've seen:
Boris
きゃりーぱみゅぱみゅ (Kyari Pamyu Pamyu)
Sekai no Owari
ゲスの極み乙女 (Gesu no Kiwami Otome)
Polysics
Androp
Capsule
キュウソネコカミ (Kyuusonekokami)
Zazen Boys
でんぱ組.inc (Dempa Gumi.inc)
ヒトリエ (Hitorie)
ミラーズ (Mirraz)
N'夙川BOYS (N'Shukugawa Boys)
Indigo la End
Okamoto's
きのこ帝国 (Kinoko Teikoku)
Scandal
爆弾ジョニー (Bakudan Johnny)
ザ50回転ズ (The 50 Kaitenz)
i-Rabbits
Rhythmic Toy World
Bradio
Phatmans After School
メシアと人人 (Messiah to Ninjin)
Honey
テイヘン (Teihen)
Meteor
Mars Violet Love
オータムソードフィッシュ (Autumn Swordfish)
0.03
The 5pm
The Fuck'in Loveless
百長 (Hyakuchou)
岡田ピロー (Okata Piro)
クウチュウ戦 (Kuuchuu Sen)

I think that's everything. With the exception of Melt-Banana and Boris. They were all in Japan.

All groups I saw were at Japan Expo lol
SCANDAL ,Ra:In,Gari,SEIKIMA II,Hemenway,X japan (just Yoshiki and Toshi , 3 or 4 songs )and another group ,maybe Catsuomatic death .Ah and Kanon Wakeshima just for 2 or 3 songs too lol.If I remember well one year there was MEG during a fashion show .
and at a festival in my town I saw Shibusa Shirazu Orchestra