This may sound weird at first but by the end of this post, it shouldn't. But in order for me to explain Imaishi, I feel the need to explain Kanada first. Or more specifically, the Kanada-school of animation. And so, we first discuss Yoshinori Kanada, and his contributions to the world of anime.
So, who is Yoshinori Kanada? Actually I should probably started with this guy after the intro as he is one, if not the, forefather of modern "sakuga" animation. He was born around 1952 and died at a very early age of 57 due to a myocardial infraction, sad. He is best known for his OVA work on "BIRTH" which is very boring and confusing unless you're an animation enthusiast and therefore will be golden. And the Kanada-dragon which will be discused later on. To continue, he was heavily inspired to become an animator by Hayao Miyaaki's Sora Tobu Yureisen whom he later on worked with. Although participating in a lot of productions, he never once became a director, unless you count an animation director as one. He's just that guy who's really good at animation and became famous because of it. Him expressing freely through his work by being that radical guy who always had to deviate some stuff on a given story board, inspired other animators to have their style on their own and impress people. And that, gave birth to the modern age "sakuga". It's that individuality of animators that differs from western animations*.
Kanada's style is best known, other than that dragon, is those pose to pose style and his artistic block/box shading style. By pose to pose, I meant POSE to POSE. It's not key frame poses but real poses like super sentai poses. He goes from one pose, to another and the transition of those 2 poses is an over-the-top exageration of the moving object and or special effects. I'd like to emphasize a bit on his block/box shading style. You'll usually notice in his style when a character (or even a lettering style) has lighter-shaded parts and darker-shaded parts, with a bonus of some shinies.
Darker shaded parts
Lighter Shaded parts
onto the other stuff
BIRTH in a nutshell: www.youtube.com/watch?v=u1Ww8xh0ivg Notice how it looks so good? Yeah... NEXT!!
You may have probably seen a Kanada-dragon already and you just don't know that it is that. Probably as a lightning effect, or just straight up dragon summoning scene. It was somewhat inspired from a sequence from Adieu Galaxy Express 999, where a ghost was formed like water and smoke.(I'll probably put a snippet later.) It made a bit of an impact to the current growing animators at that time, and that style was polished by Kanada by using it on a scene in Harmageddon as a dragon and was dubbed as the Kanada-dragon.
Here are some examples of the Kanada-dragon. The first part before the BGM starts is from Harmageddon.
I'd like to show more modern Kanada stuff but...it's hard. So here's a video of how his style was used across a ton of anime.(Most are not by him, but used the Kanada-school of animation)
Kanada-school of animation is so vast that it's hard to tell who animated a scene when his style is used, that's how influential this guy is. There's also a lot of deviations from it. And the most noticable deviation, or some say evolution, is from Hiroyuki Imaishi, which most are familiar who worked on...DIEBUSTER or Tengen Toppa Gurren Lagann And now is the founder of Studio TRIGGER.
*In western animation, a scene is done by a lot of key animators. On a scene with a cat, a car and an explosion, there's probably 3 key animators working on that. One for the cat, one for the car and one for the explosion. I think I forgot to mention this on the intro. I'll just crash it here for now