Yesterday, I spent upwards of two hours fighting the same 6 Yus in Ranked (it was a pretty big pain in the ass). I did, however, learn a few ways to keep them out that I feel like I should share. I won't pretend that I'm the best Yukiko in the world by any means, but it helps to have something to chew on, right?
What I've seen a lot of in C+~ Yu-play is that they'll rely a pretty good deal on Raging Lion (sword-dive) that has to be blocked high, which was an issue because I typically try to block low to avoid any surprise lows. The general mix-up here is his 5D (low) into Raging Lion (high), so my strategy thus far is, as soon as I see Izanagi appear and set up for the dash, block low, then anticipate the high and switch up really quickly, and try to wake up with 2A into the usual BnB, or 5A+B in case he tries to follow up with 5A or something.
The other pitfall I typically fell into was falling for the slide, too. I would try to evasive dodge out of it, but either due to mistimings or the hitbox being too large/lasting too long, it generally failed. SupaN10doh mentioned about countering it with an all-out attack (page 1), which is my personal preference on beating it (but I feel like I use all-out attacks more than anyone else I ever play against, which I think is partially due to me learning via stick. A friend commented on it, saying that I used it a lot more than most other people he's come across, and we deduced that hypothesis), however, I'm completely out of sync with him on using a One-More Cancel. I just follow up with the launch->j.A->j.A->j.C->JC->j.A->j.C->Agi combo outlined in the combo thread, as it does fairly hefty damage and, if timed properly, you can get out a Maragi before they hit the floor for another follow-up of your favorite flavor (I haven't really experimented with this, though).
The main issue I have is getting to know his mix-up, because he can practically string one combo into another complete combo with very little room for punishment, particularly in the corner. However, once you learn when and how to block your opponent, like what Choysauce85 was saying, they'll have to go to other moves in order to get damage, which are, in my opinion, easier to counter out.
5BB will counter out Zio, obviously, and I've had Yus try to zone me from being able to, say, 5D with Zio, or bait out 5BB with one, then slide under the second to get in. Be wary of the traps, but for the most part, I think that Yukiko is too underplayed for Yus to know that we have two fans, haha. At least, I've never ran into one.
Typically, my opening gambits are low-guard for 5D or slide, high-guard or evasive action in if he jumps to block out that stupid sword-dive or instant-dash j.A if I'm feelin' aggressive and he looks like he's gonna jump or do something silly. Mostly, I go with low-guard, and if he evasive dodges in, I'll try to catch him in a throw, and follow up with 5D combos.
Thoughts?