I recently purchased and viewed bladesmith Murray Carter's video. I reported
awhile back on Korin's video. Carter's is much more comprehensive on the 6
basic steps of sharpening. He does point out that there is no magic bullet
and that practice is essential to successful technique. Having viewed it a
couple of times, I think my understanding of technique is much better and
that my results prove that.
On the downside compared to the Korin video, he does not specifically
address sharpening traditional one sided japanese knives. If you want to
learn to sharpen sushi knives the Korin might be a better choice, however I
am sure that the basic principles Carter discusses still apply.