1967 saw the first Jan Kjellström International Orienteering Festival or "JK", held in memory of Jan Kjellström. The annual JK moved to Easter in 1969, and now regularly attracts a field of four thousand or more. The 1974 JK was the first British race to attract more than one thousand entrants. The JK Trophy is awarded to the winning team in the Men's Premier relay class.
References
Jan Kjellström International Festival of Orienteering Wikipedia(Text) CC BY-SA