Quote Originally Posted by tehlegend
in responce to earlier talk about rasengan. the size of rasengan cannot be used to determine the power. you people say that rasengan must be bigger to do more damage, however a greater size only means less control, as it is less concentrated. jiraya demonstrates this during narutos training. therefore, we cannot tell if kakashi's rasengan size is due to lack of power or extreme overload of it. the smaller rasengan is, the more concentrated the power, the faster the spin, and the more destructive it is.
But then there's Naruto's oodama (sp?) rasengan, which he used against itachi. I believe that was distinctly larger than the usual rasengan he uses.