Kickboxing vs Karate
Kickboxing was invented by karateka, twice, on two continents. The differences that remain are almost entirely about what each competition format asked for.
This comparison is complicated by the fact that kickboxing came out of karate. Tatsuo Yamada wanted a full-contact competitive karate and worked with Noguchi to build one. American full-contact kickboxing was created in the 1970s by karateka who wanted to fight rather than point-spar. Ishii's Seidokaikan, which founded K-1, was a Kyokushin offshoot. The lineage is direct.
What separates them now is the competition format. Point karate — the WKF style seen at the Olympics — stops after each scoring exchange, rewards the fighter who lands first, and permits controlled contact only. That produces explosive single entries from long range, immediate withdrawal, and no reason to develop the ability to absorb or exchange.
Kyokushin's knockdown format is full contact but bans punches to the head. That produces extreme body conditioning, head kicks as the primary knockout weapon, and — because nothing has been thrown at their head with a fist for years — very little head movement.
Kickboxing's format is continuous full contact with head punches, which asks for all of it: the ability to exchange, defend the head, absorb, and work at both ranges.
What karate brings when it crosses over is genuinely distinctive. Andy Hug's axe kick, Francisco Filho and Glaube Feitosa's spinning attacks, and the long-range explosive entry all come from a format where the first clean strike ends the exchange. What it has to acquire is head defence and the willingness to stand in a pocket, and that acquisition usually happens in public.