After the backhand in naihanchi kata, the next movement is the pulling elbow. This technique seems pretty straightforward - you're grabbing someone by the head and pulling them into an oncoming elbow strike, right?
- What if you're not grabbing them - what if they are grabbing your wrist?
- What if you're not striking with the outside, sharp/hard surface of the elbow - what if you are striking with the inside crook of your elbow?
- What if you're not pulling with the pulling hand - what if you are using an open hand to point to your own elbow as a reminder to yourself to attack or focus on the opponent's elbow?
These are actually a couple of my favorite alternate applications besides the blatantly obvious (but very effective) grab-and-smash.
- Opponent grabs your left wrist with their right hand - you countergrab with your right hand on their wrist and smash your elbow into theirs, releasing their grip and pulling them off balance (in preparation for the next move of the kata)
- Opponent grabs with his right arm around your left side/back as if for a hipthrow or bodyslam - you strike across in front of your body, trapping his elbow/forearm against your side and hitting his reaching elbow with the inside crook of your elbow.
In kata in general, and naihanchi in particular, nothing is just the one obvious thing that it appears to be. That is part of the genius of well-constructed kata like naihanchi - the kata never teaches you just one thing at a time. Not only are there no wasted motions, but all the motions are very multi-purpose.