Venusian aikido

Venusian aikido was an unarmed combat style developed on the planet Venus, used frequently by the Third Doctor to defend himself and others.

It could be used to immobilise an opponent by utilising pressure points (DW: The Mind of Evil), as well as perform joint locks, throws and kicks. These were effective against many different humanoid species, but seemed useless against non-human duplicates (DW: The Claws of Axos).

The Venusians who created the martial art had multiple limbs and appendages, which must have made mastering their aikido difficult for a humanoid.