You don't need to hook the leg to do osoto gari. I've hit this move in real matches before, so I know what I'm talking about. If you watched the gif you posted, you'll see that he doesn't hook, he simply sweeps the leg upwards. I don't know why you are stressing hooking the leg so much, because that's not how it's done irl.

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Please point out where the leg is hooked.




OH WAIT!!! THERE IS NO HOOK!!!
If you translate osoto gari to layman terms you get "large outer reaping," not "large outer hook."
You don't need to hook the leg, lol.