The founder of Kyokushinkai, Masutatsu Oyama, was born on July 27, 1923 South Korea. From the age of 9 Oyama studied Chinese Kempo. In 1938 at the age of 15 he travelled to japan to live and enrolled at the Takushoku University. After mastering judo he began training Okinawan Karate under the tutorship of Gichin Funakoshi (the father of modern karate). By 17 he had achieved 2nd Dan and by 24 he had achieved his 4th Dan. In 1946 Sosai went to train on Mt. Kiyosumi in Chiba Prefecture. Following this training he competed in the 1948 he took part in, and won the all Japan Karate Championships. Following this Sosai once again isolated himself from civilisation and took to training in solitude in the mountains to perfect his art and his spiritual self. Once this training had been completed he went on tour around the world and gave many demonstrations of his abilities including the now infamous fights with bulls. There are many accounts of these fights but it is believed that he fought 52 bulls, killing 3 instantly and taken the horns of the remaining 49 with knife hand blows. He also toured the USA doing live regional and national television interviews and demonstrations.
During his lifetime Oyama performed a number of feats including defeating a number of bulls with his bare hands and also completed the 100 man kumite 100 full contact, 2 minute rounds in which the competitor must win at least 50% of them and if knocked down must return to fighting position within 5 seconds).
Upon his return to Japan he opened his first dojo in 1953 in Mejiro in Tokyo. In 1956, the first real Dojo was opened in a former ballet studio behind Rikkyo University, 500 meters from the location of the current Japanese Honbu dojo (headquarters). By 1957 there were 700 members, despite the high drop-out rate due to the harshness of training.
Sadly, Sosai Oyama died of lung cancer on 26 April, 1994 aged 70. Since then the main body of Kyokushinkai has split into a number or smaller organisations (of which the IFK is one) much the same as Shotkan appears to have done.
Even with these changes Kyohushinkai today is still firmly rooted in the training principles developed by Oyama with tests of physical and mental perseverance such as the 100 man kumite still open to students if they wish to test themselves there are also 20,30,40 and 50 man variants-still no mean feat as anyone who has fought in a knockdown competition will testify to! To this day Kyokushinkai is well known and highly respected within the martial arts world and is still known as "The Strongest Karate".
History obtained from Crawleys website:
http://www.butlersoft.co.uk/bkk/default.asp?pageid=202&heading=Kyokushinkai%20History