Ahh I think ive worked it out....
In razors edge, the Ninja trials are done by the main characters only so it will 58 trials in total in the 360/PS3 version
then you have the clan battle with the generic ninjas which is the free-for-all mode.
On top of that you have a Test of valor in every level....8 in total.
so this game has 65 missions outside the main game and each level can be played by each character in chapter challenge mode as well?
on top of that each trial can be played solo and co-op?
and they average 10 mins each?
Your issues with the vanilla release aside, This is by far the most content rich action game this generation.
long as you can stomach hayashit's downgrades in combat, you could comfortably play this game years from now.