Rules of kosen judo :
match 25 + minutes
Ippon from Throw , pin , choke , armlock
no stand up, hikkomi allowed (pull to ground) , no Wazari/Yuko/koka
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Maeda, as Ito, Ono and the other judoka that travelled, teached and fought were Kodokan.
The greatest innovation in term of newaza came later, with Kansai School of Judo, a group of teacher that developed the newaza and teached in the school (kosen).
The Most importan master in term of newaza was Sensei ODA. Untill his death he was the personification of Newaza for judo , and all the official Kodokan book about newaza were written by him.
Oda was the developer of Sankaku jime(triangle choke) in all his variation
Sankaku and other moves developed later than the years of maeda at kodokan, come to brazil later with other judoka (like Mehdi, Kimura, Ono , Osvaldo Alves, student under Okano, and others).
Here 3 video of ODA showin Newaza
http://www.youtube.com/results?search_query=Tsunetane+oda+judo&search_type=