Complex sentence: In 1965 Judo training was added as part of the Krav Maga training and until 1968 there were no grades in Krav Maga and then trainee's grades were determined largely by his knowledge in Judo.
Split into simpler sentences: In 1965 Judo training was added as part of the Krav Maga training, and until 1968 there were no grades in Krav Maga. Then a trainee's grades were determined largely by his knowledge in Judo.