Activation time of 7 day JR pass

Hello!

I am visiting Japan for 13 days in September and my itinerary is as follows:

Toyko Sept 4-5 (travel to Shizuoka morning of the 6th)
Shizuoka Sept 6
Kyoto Sept 7-9
Osaka Sept 10-12
Tokyo Sept 13-16

I had a question about the 7 day JR pass. I was planning on activating it on Sept 6, from Tokyo-Shizuoka, is the day I activate it day 1, or day 0? I guess I am asking if the last day the pass is active would be Sept 12 or Sept 13?

Also looking for any recommendations or comments about the itinerary and things to see!

Thank you in advance