Some people just look at it and chalk it off as Harai with a funky grip. But as someone who likes both, I can tell you that the grip makes all of the difference. Generally speaking, when you throw someone with Harai you will feel the pop and get them up in the air, and if you land it with the opponent in the right state of unbalance, he or she will definitely fall for an Ippon in your favor. However, when executed from a point of weakness it is hard to get the full force of the throw sometimes.
Enter Yama. With Yama, I actually feel my hands driving my Uke towards the mat with both speed and force! It's hard to get the thumb inside the same-side lapel grip, but if you do, you are definitely winning the match. It is probably the most powerful throw in my arsenal.
If you can't find it in a good book or website, here are the basic steps:
- From Hidari Shizentai, push uke so that s/he reacts by stepping forward, shifting his/her weight to the right foot.
- Release your right hand from Uke's left lapel, and proceed to turn into Uke as if throwing Harai Goshi
- Quickly Grab Uke's right lapel with your thumb inside his/her Gi Jacket and pull Uke onto your hip as in Harai Goshi.
- Throw uke with your hip while pulling down on Uke's gi and sweeping Uke's right leg with your right leg.
- Smile - you won the match :)