Not sure if I posted a similar reply but the ignored ne-waza of judo (after 1945 ???) became the BJJ of Gracie and whjat we know today as the latter art. Maeda studied Judo but it seemed that after the war, only throwing appeared to have been emphasized in modern Japan so when he taught the ground techniques, everyone thought that it was new when it just was not practiced post WW2. The Brazilians became naturals of BJJ as it approximated their sport art of capoeira!