Hello, Hi, Hiya, Bonjour, Dumela, Asalaama Alaikum, Hej, Namaste and more! When I decided to forego my beloved pentagon and hexagon patterns in favour of hooking the "Little Karoo" throw in a basic square a month ago, I simply couldn't remember at what stitch to start and end a Granny Square. In hindsight I am glad since the majority of squares start and end each row in such a way that the chain stitches that form the first US dc are highly noticeable throughout the project. Below are a few photos detailing the way I start my squares which also happen to hide the joins 100% - a pattern that emerged out of not knowing how others do it. Anyway, it might also be that this method is well known but I haven't surfed the tinternet yet to verify, so this is the Pigtails join for the time being.
You will also notice that I do not put a chain stitch between my clusters in order to keep the squares tight and uniform. I also only chain 2 instead of 3 stitches in order to create a US dc. I demonstrate by joining a new colour but the method remains the same irrespective of colour changes.