Genfu (i10/i11/i15) vs Kokoro (i10/i12/i13)
Genfu is very fast at i10 and i11, his low jab is slow but it is neutral (+0) on hit, -4 on block. His K is also fast at i11 and is a high kick. +4 on neutral and -9 on block. A really good tool for stun and for interrupting something (outside of his 6P). His 6P is his i11 mid punch, his 4P is i13 (4P6P is a very good block string and it retracks on side step attempts).
His 3P is also a mid punch, i15 frames, and is considered one of the best hi crushes in the game (for good reason). It's a lift stun on counter hit and in Criticual stun. Not exactly something you can stagger out of at all. As 3PP will just put you in his crumple stun, guaranteeing the rest of his follow ups into either a 3P relaunch for air throw into vortex OR crumple ground stun into 80-100 damage with a close hit.
3P's stun puts you into a lose lose situation. You cannot stagger out of it, because 3PP sits you on your ass, or 4P+K puts you into a faint stun and guarantees a 64P crumple ground stun for damage. You are put into a "must hold" situation if you are caught by Genfu's 3P lift stun.
His 3K is i14 and is a very good mid kick with follow ups. 3KPP ends with a high punch and guard breaks, 3KP6P ends with a mid punch but is throw punishable on block. 3K leads into good block string pressure, and forces you into a must hold situation because it has follow ups he can and will get away with if you don't hold. On hit, 3KPP guarantees him a 6PPP juggle. For 3KP6P on hit, he's guaranteed a 214PP follow up.
His 44P is a very good guard break. Linear and slow, but difficult to side step because it's hard to see when it actually is extended out to side step in time, and it's chargeable. It can be mixed into his block string pressure to break your blocking since you will not expect to see it. And it's extremely good when mixed into his vortex.
Guarantees him multiple follow ups to continue his offensive pressure, air throw into vortex, or just gets him damage.
He has a high AND mid parry. Both guarantee him an 8PP OR a 4P6P for Critical stun into a favorable mix up.
Genfu can shutdown a lot of Kokoro's offense. She has a sabaki and a mid punch sabaki. Her original sabaki is barely viable against him because his K is really good, and sabakis lose to throws. Her mid punch sabaki is throw punishable on block, and it's timing is far to strict to keep Genfu's 6P in check. Her lows lose to his 6P and his 4P. His 4P6P will counter hit her side step attempts for sure.
His 3P crushes her jab and high pressure too well. His jab AND his 6P counter hits her Heichu option selects clean outside of stun.
At range, she has more to fend him off than he does against her. But after getting so comfortable playing with Genfu, he does not have problems inching his way in on characters, especially because his 66P has very good hit priority and is only -5. His 214PP is also really good to step in with, stuns on neutral, and is only -4 on block with push back. All it really takes is good patience to get in with Genfu (Sweet Revenge will tell you the same thing and his Genfu is much better than mine). Being an Ayane main, she requires me to play patiently anyway. I carried that over to Genfu.
Kokoro can definitely fight Genfu, it's a matter of breaking his strong offense AND defensive game to keep him from doing so much. Because if he stuns you or throws you with 214H+P or 236H+P, things get shaken in his favor.