The chain wheels and cogs look good. I built the bike 9 months ago so i don’t think anything is worn yet. I don’t do any power shifting to lower gears. That just seems like a bad idea.
I don’t usually stand and power up climbs, but some time i don’t choose a low enough gear for the climb or rider in front of me suddenly slows. i stand up and power though the climb instead of shifting to a lower gear.
Looking at the chain this morning i see that the chain is breaking in the same spot. Maybe that link of the chains is messed up. I am going to replace that link with some of the spare links i have.