This is a series of events at Cobalt to promote coding as fun activity.
The word «kata» can be translated as «form» from Japanese. In martial arts this is a choreographed pattern of perfect movements to be practiced by a disciple. One might call it a combat with an imaginary adversary (or multiple). This is an exercise for corporal memory, so that movements and their series were executed almost «automatically».
Similar to martial arts kata, code kata is also an exercise. And same as imaginary combat will never happen in reality, the tasks solved in code katas are not the ones an Engineer faces in their day-to-day job. This does however bring useful thought tropes and helps to achieve clarity in such things as «TDD», «testable code», «specification», «mocking» and so on.
It is also much fun.