Anybody knows wich technique is stronger "Three Thousand world" and "Ashura" (Zoro's Technique)?

Ashura is way lebih powerful. tht's why he used it against Kaku. It's a form of haki,which is a special technique only a few people can do,luffy and shanks share this ability.shown first when shanks shooed away the sea king trying to eat him and luffy,and also when luffy and bonchan r in impel down and luffy blasts away all those wolves.so its kinda like going gear third in a way,but for zorro.

of course ashura but he will only use it in special situation

ashura...

it is amazing technique !!

Asura...
That kind of weirds me out, though. I don't understand exactly what happens...