0 frame grab

How does this work exactly? There has to be more to it than just ducking and grabbing??

 

Zero frame grab is one of the most powerful tools in the game. It means your opponent can not just stand around and block. If they do, you can throw them and they get no warning (no throw animation). This is why you see a lot of Japanese players crouching (you have to know how to do this also, so you can still notice when a mid is coming to stand and block). There is also a counter strat to this. It involves waiting, then throwing when you think your opponent might stand. Since throw is zero frames, you will catch an opponent as he is rising if he isn't rising with an attack.

 

From virtua fighter 5 system faq:
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Normally a throw includes a grab animation before it connects. This grab animation lasts for 12 frames during which time the opponent can initiate an attack or duck/rise to interrupt or avoid your throw. Zero Frame Throws however execute without this animation.

Any High or Low Throw executed when the opponent is passive will execute as a zero frame throw. This means an opponent that is either standing still or blocking, whether crouching or standing for low and high throws respectively. Zero Frame throws will also occur if the opponent is in a Catch Throw animation. </div></div>

Its an important read for beginners, look for it from the virtua fighter 5 pulldown menu on the left.

 

In response to the first post:
Yes, it is as easy as just mashing out a throw while ducking/slipping because the opponent has a certain window after getting hit or blocking an attack during which time 0frame throws will not occur (10 frames if I remember correctly). The slipping/ducking animation is longer than this window so you automatically delay into a 0frame throw without having to time anything for yourself.

A simple example is mixing up between /forums/images/%%GRAEMLIN_URL%%/f.gif/forums/images/%%GRAEMLIN_URL%%/p.gif(hit)/forums/images/%%GRAEMLIN_URL%%/f.gif/forums/images/%%GRAEMLIN_URL%%/p.gif/forums/images/%%GRAEMLIN_URL%%/p.gif and /forums/images/%%GRAEMLIN_URL%%/f.gif/forums/images/%%GRAEMLIN_URL%%/p.gif(hit)/forums/images/%%GRAEMLIN_URL%%/f.gif/forums/images/%%GRAEMLIN_URL%%/b.gif/forums/images/%%GRAEMLIN_URL%%/p.gif+/forums/images/%%GRAEMLIN_URL%%/g.gif. The former beats low-punch/crouch while the latter will grab a blocking/dodging opponent in a 0-frame animation, this mixup is also harder to employ fuzzy guard against because of the odd timing.

aside:
I actually wrote that bit you quoted there (*snf snf, does a man good to feel useful). Now that I read it again I realize I have to see if that bit on catch throws at the end (tested with Goh's /forums/images/%%GRAEMLIN_URL%%/f.gif/forums/images/%%GRAEMLIN_URL%%/f.gif/forums/images/%%GRAEMLIN_URL%%/p.gif+/forums/images/%%GRAEMLIN_URL%%/g.gif, which the AI will throw you out of all the time) extends to the normal grab animation of throws as well, I think it does.