More and more, I see (or have pointed out to me) similar techniques across different kata. They are not all identical, but have the same intention or principles behind them.
Some of the ones I have encountered recently are:
- Head/neck grab and crank: saifa, sepai, seisan, sanseru (seienchin as well, but not in the tradition I am training in)
- standing arm bar: seienchin, saifa, shisochin
- different standing arm bar (I've forgotten its name): kururunfa, sepai
- escape from rear bear hug: shisochin, seienchin, seisan
- guardian opens and closes the gate: saifa, seienchin, seisan, kururunfa, shisochin, hakkucho
- escape from front bear hug: kururunfa, happoren, shisochin
- leg takedown: sanseru, kururunfa, tensho (with interpretation)
- shoulder wheel throw (kata garuma): kururunfa, shisochin
- front strangle escape: seienchin, shisochin, happoren
There are plenty of others, too. It raises the question: Why have so many kata, if there is so much overlap? But that's a question for another post.