Guitar in live performances

[PrincessAyu]

Remember the lives of "appears" back in 1999? Well, the guitar you hear there sounds exactly like on 'LOVEppears'... so I'm wondering, was Yocchan really playing guitar? Was it live? I bet it was O_o I mean... why fake play guitar or something, but it sounds exactly the same. It seems impossible XD or really amazing. XD With "INSPIRE" or "GAME" live I could clearly hear it was live, but now with "STEP you" I can't, also with some other songs I dunno if it's real or not. I believe it is, I'm not sure. But then there's another question. They DO play the background music, but then what, is the guitar sound cut out and is Yoshio playing it live, and SO well that you can't hear a difference with the real song [when it's not live]? Or is he playing along, but with the guitar sound in the song? ... and how do they do this in concerts?

... I'm confused [sorry if I confused you too ^^;;] XD I have no knowledge whatsoever about guitars, so sue me XD but does anyone know about this? Please tell me ^___^;