Some ranking lists more or less choose themselves, but deciding on the best No. 8s in rugby history is a task that will cause much debate.
A quality No. 8 usually distinguishes himself by being a jack of all trades. They are defensively strong at close quarters and in the wide channels, fast and powerful with good hands, able to control the ball at the base of the scrum and able to provide an option in the lineout.
Not all the players on this list meet that criteria, but most do. And while there is plenty of room to disagree on these players being the best six, there is no denying they are all No. 8s of great distinction.