this is what I find... it was in spanish, its a google translation, (im too lazy to translate the whole thing, but its pretty accurate for what I could read)
Kosen Judo has the same projections and other techniques of Kodokan judo but stresses much work newaza (judo techniques such as soil, locks and chokes), giving greater scope in carrying out the same as in the battles of Kodokan Judo . Judo is a style that is widespread, some even see in it a clear relationship with the birth of Gracie Jiu-Jitsu or Brazilian Jiu-Jitsu, a fact that is not entirely proven.
The birth of this style of judo takes place at universities in Japan that had judokas lighter and smaller than others, at a time when competition is not yet differentiated pesos. These judokas found it much harder to win the battles for projection. So focused on newaza (Judo ground work) as a way of getting points in competitions.
During the evolution of this style Kosen Judo and until he adapted to the Kodokan judo, they were dominated in numerous competitions for style Kosen (Kyoto University was its greatest exponent in front of the Kodokan Judo in Tokyo, beating the first up to 16 times from 1926 to 1943-the beginning of World War 2-). So much so that Jigoro Kano himself had to intervene by establishing, in just these competitions, three new rules: the limitation of time the Judoka could stay on the ground, and the new rule that anyone who throws his opponent in three sometimes be proclaimed winner of the bout. In 1925 Kano these rules would extend to all the judo competitions.
Later Jigoro Kano Judo championships organized for universities Kosen, leaving this style of martial art sports both defined as Kosen Taikai. In this style practiced until today in schools of Japan and around the world will not respect the time limits of grip on the floor.
The style Kosen Judo was always associated with the imperial universities, those closely connected with the Japanese army. The presence of the Americans after their victory in World War 2 was higher in these universities associated with the Japanese military, so they paid close attention to this style.
Jigoro Kano always respected practice Kosen schools, and these continued their training course as they had done since the early twentieth century. Even today in Japan is celebrated Seven Universities Tournament (Kosen) in which the fighting is governed by the old rules. Kano when he introduced the new rules was careful not to delete the Kosen Taikai, for several reasons: