I filmed these for Derek, but I decided to put them in their own thread for the other gi grapplers here. These two throws take years to master, so we claim no expertise. However, we did a serviceable job, the video quality is pretty good, and it includes each throw in slo-mo.
Harai goshi (thrower is Devin, age 12).
Devin has won several junior national championships, and his version of the throw has been a big part of it. Notice how tight the pull across his thigh and hip is. As you see, he generates enormous speed as he executes the throw (which is why I over rotate on the slo-mo version).
Uchi mata (mine).
I throw two with a back grip and two with a collar grip in this one (I prefer back, but a collar grip is more likely). The keys are a deep left step (for mine), a hard pull on the sleeve, and pointing your nose straight down. The first slo-mo has regular footwork. The second one has the more tourney-style dynamic footwork.
Both of us are 100kg players right now, so it's not quite as dynamic as the little guys. Neither of us sweep the leg very high, but we don't need to. If you get a good pull and correct thigh placement, your opponent will go flying.