In one of the study groups I am a part of, the nami-gaeshi (returning wave) movements from Naihanchi was brought up as one that doesn’t often have applications shown for it. This movement is also present in some versions of Passai, Kusanku, Seisan, and more! How could something so common and distinctive have no practical application? Well, it does have a practical application–more than one, actually–so I set up my camera and recorded the first 10 applications that came to mind.
There are certainly more applications, but most of the ones I can think of are variations on the list, above. In addition, those variations are quite subtle, and difficult to illustrate in a short video. For now this will at least give you some simple material to incorporate into your training, if you haven’t worked any applications for the nami-gaeshi movement. If you have learned some applications for it, then hopefully this shows you at least one that is new for you.