I really like the hip check version of O Soto Gari (Major Outer Reaping Throw).
For classic O Soto, this is a great video:
The important part of the entry is fixing the opponent's leg to inhibit mobility, not for Kuzushi or breaking balance.
Inhibiting mobility is what stops counter throws. Like many of my favorite throws, the approach is not what breaks balance.
Instead, after you have made your entry and fixed your opponent's leg to stop mobility, you go hip to hip rather than just behind your opponent. You do not break his balance backwards. Instead, you hip check your opponent and lift with the throwing leg into the opponent.
When I was serious about the throw my competition weight was around 172 (no longer a weight class, they moved the boundaries). My weight training for the throw included 20+ reps at 240 pounds on abductor exercises.
Only after your opponent is off the ground do you engage in throwing torque and at that point your instep also catches the opponent's lower leg in a sweep.
It is a very forceful throw.
Variations:
One, your grip is right hand to the inside lapel (the opponent's right lapel) rather than the traditional behind the head or left lapel.
Two, your grip is a "no hands" (no hands on the Gi at the start of the throw), where you punch your right hand past uke and you parry his right hand with your left hand (and push it up and past your right ear).
Three, reverse grip. You stand right, grip left and throw right. Often the hip check does not make it all the way to side by side, and the torque is more like an Uchimata after uke is airborne than it is an O Soto.
That is the classic Kimura O Soto. But in the third frame where he is reaping, there is a hip check. Only after the hip check has raised uke from the ground do you have the fourth and fifth frame torque for the throw.
The follow through is sitting out into Kasa Gatame. Your goal is to transition into the pin as you are hitting the map. Landing in a pin is one of the strongest ways to get a full point for a throw.
In a real fight, your goal is very different. I will not be discussing the differences here.
