Thanks to you both, that really helps me.
I also remembered the official Blazblue tutorial videos, on a DVD, and found the entire list of the best combos for Jin, I'm currently training on them =) I have some difficulties to stay in range with the opponent, for 5B 5C 9 JB JC JD 214B. Here my JD barelt hit the opponent, if most of the cases I fail at it. Same thing for 6C 66 5C 9 JB JC 9 JB JC JD. Here again, my last JD fails almost everytime, I guess I'm too slow.
Is there an option in the training menu, so the AI doesn't block or move or hit, but tries to retaliate (I guess it's the word) when they are in air ? I saw that succed at comboing a simple Dummy, but as soon as I try on a real opponent, they retaliate during my combos, so I fail at finishing them. I guess I'm too slow...
But anyway, learning combos is good, but I think I should learn zoning first, I really suck at it... And jumping on my PSP is a real pain in the ass, because my (dunno the word, the controller) is a bit broken and it's almost impossible to do 9, 7, 3 or 1 alone.