KotH (short for King of the Hill) is the most well known of the arenas for Core Wars.

It is completely email driven, with people sending in email messages consisting of the program to enter and the arena to enter it into. The new program is then run in 100 battles against each of the 20 current programs on the hill. The program receives 3 points for each win and 1 point for each tie. Scores are then updated and programs are sorted by score. The 21st program is then thrown off the hill.

The original KotH was run at Intel in 1991 and ran for 3 years. Until 1995, two different hills were run with overlapping setups: koth@koth.org and pizza@ecst.csuchico.edu. Currently, the different hills offer different setups.

Sample entry:

;name Dwarf
;author A.K. Dewdney
;strategy Throw DAT bombs around memory, hitting every 4th memory cell.
;strategy This program was presented in the first Corewar article.
bomb  DAT   #0
dwarf ADD   #4,    bomb
      MOV   bomb, @bomb
      JMP   dwarf
      END   dwarf