How to win at Sumo wrestling

In the matter of Chiyonokuni vs Takanoyama on Day 7 of Hatsu Basho 2013, YouTube commenters note that the winning manoever, a Henka sidestep, is generally considered bad form, but in this case the larger wrestler had earlier disrespected the smaller one, so it's all cool.
The spank really makes it, doesn't it?
Here's another example of a Henka:

Here's a failed Henka (bout begins at 6:20m), though it still puts the wrestler at an advantage and he soon wins the bout: