Okay, I'm just going to say this now so people can stop sounding like noobs throwing the term "OP" around so much.
genfu cannot really open you up on block UNLESS he attempts to throw you. He really doesn't have anything in his strike arsenal that screams "mix ups". You block him correctly, he has to throw you. This is where counter hits come into play. If you are not reacting to his i10 or i12 throws, then yes, you are going for a ride.
Most of genfu's play consist of this;
- Neutral pokes you enough to stop blocking so he can initiate his parry/3P defense.
- Neutral pokes you slightly in an attempt to throw you. Smart genfu play will keep you in check with an i5 or i7 so you can't react to throws, you guess instead. Typical genfu will always attempt an i10 or i12, you can certainly react to the slower speeds like i10 and i12 throws.
- Tries to keep your neutral/counter pokes in check with P, 6P, 4P6P 2P, 3P and K (K is throw punishable). genfu's 3K is i14, he cannot keep you in check with this in CQC for counter poking.
His 1P is also -4 on neutral hit (low throw punishable on block), so he has to be defensive if he makes his next move.
Let this sink in for a bit, there are characters that can fight genfu. You can't use every tool in every single match up your character has. Some tools are more effective than others in certain match ups, some are not. Think carefully and take your time in the lab to figure things out.
I'll say just this bit as an example, everything in Hayabusa's ninpo stance up close loses to Ayane's 6P.