Harai-goshi, favourite of many, is one of the corner stones of Judo. I would have thought that this technique evolved from
O-goshi - from an
O-goshi attack the opponent tries to move off the hip, the thrower lifting the leg, preventing the opponent's escape and subsequently throwing them.
Of course, Harai-goshi has evolved from then - whilst the above example is still a valid technique, it is more of a continuation from and
O-goshi rather than a technique in it's own right. To perform a Harai-goshi right handed on a stationary partner, turn in as you would an
O-goshi, ideally with the right hand around the opponents back (the hand is, however, free to be on the collar or your favoured grip). Then lift the right leg foward, thus lowering your rump below your opponents, and then sweep the right leg backwards - lifting your partner and then throwing them off of your hip.
