I Don't Understand37,203 Views SingerKagamine LenVocaloidProducerKurokawa MasakichiProducerViews BreakdownNiconico30K ViewsYouTube7.1K ViewsDaily Views311/01211/02211/03211/04211/05011/06011/07VideorefreshRefresh Song DataListenYouTubeNiconicoVocaDB