Board Thread:Naruto Discussions/@comment-26135923-20150707130017/@comment-734582-20150711140426

Chaosattractor wrote: By "every generation" I obviously don't mean "once every 25 years". Even if it was every sixty years or so, that's 16 times fresh pure chakra would be entering the Senju/Uchiha lineages. Maybe i need to explain it better:
 * Madara lived at the time of Hashirama
 * Tobirama was Second Hokage and brother of Hashirama
 * Danzo is about 70 years old yet served under Tobirama
 * Hiruzen is old enough to have lived to see both Hashirama and Tobirama.

About three/four generations have passed since Hiruzen/Danzo. (Hiruzen -> Sennin-> Minato -> Kakashi -> Naruto). yet Hiruzen was old enough to see Tobirama and Hashirama by himself. So depending on everyone's exact ages and the exact generations, about 3-4 generations have passed between Madara and Sasuke. +/- a generation depending on