BaconIsMyBFF

Answer: If referring to the blonde in the first movie, that was Elisabeth Shue, not Kristy Swanson.

Okay my mistake but did they decline returning or what?

Rob245

Answer: Part II was mainly focused on the storyline in Okinawa. Miyagi speaks with Heller on the phone briefly (though she's not seen or heard) to say he will take care of Daniel on the trip. She was not essential to be in this film.

Answer: To add to the previous answer, Elisabeth Shue went back to Harvard to continue her studies which is why she doesn't appear in the sequel.

Answer: Ali was originally only supposed to have a very small role in Part 2. Elizabeth Shue declined to reprise the role because she was studying at Harvard at the time. I can't find any explanation online as to why Randee Heller was not in Part 2 and was barely in Part 3.

BaconIsMyBFF

Answer: Like all studio executives they think mixing things up by bringing in new characters into different settings would keep the franchise fresh. Most of the sequels from the 1980's were given minor or major cast changes.

Answer: He has showed up in Cobra Kai season 3. Daniel travels to Okinawa for business and meets many old friends including Chozen who teaches him the final secret of Myaghi Do Karate.

Answer: There has never been any explanation of what happened to any of the characters who debuted in The Karate Kid Part II. The series Cobra Kai has so far focused only on Daniel, Johnny, and Kreese while introducing new characters. I wouldn't say it's unlikely Chosen would show up at some point, Yuji Okamoto (the actor who played Chosen) still acts regularly and could easily be brought to the series if the writers decided to focus on his character.

BaconIsMyBFF

Question: What exactly is the drum technique that Daniel defeats Chosen with?

Answer: The technique, much like the crane kick in the first movie, was made up for the film. If you are asking what exactly Daniel is doing when he performs the move; he is blocking with one arm, striking with the opposite hand and rapidly switching sides. The move works as a metaphor for the overall theme of the entire series: balance.

BaconIsMyBFF