How is O'ong related to De Jong? He was part of the De Jong story in that he along with other Indonesian martial artists were guests of De Jong in the late 1970s or early 1980s. And he was dedicated to the martial arts as De Jong was.
O'ong was also an academic of pencak silat, as I am of the martial arts generally. His website with his articles is very interesting. 'The Militarisation of Pencak Silat during the Japanese Occupation and the Era of Revolution' is particularly interesting.
In the above article, O'ong writes about a homogenous training package of pencak silat. When I was living in London I came to train Perisai Deri (PD). PD was developed from different indigenous styles of pencak silat. In my mind, it follows the Tae Kwon Do model of developing a generic martial art from the indigenous martial arts to be taught en masse, such as the military.
PD didn't have the pencak silat feel that I'd come to love. I'd trained pencak silat at De Jong's school, in Indonesia and Holland, and PD was far too rigid. I went and trained with an Indonesian teaching a style from Sulawesi. Loved it. After a few training sessions he told me I had to continue training PD with the other instructor for six months and then if I wanted to I could continue training with him. This is in London in the 1990s!
I was not keen on training PD. It didn't have the pencak silat feel. So I started training with Richard De Bordes. Hardest training I've ever done. They knew who I was (an instructor of Jan de Jong) so I got 'special' attention. Also, I was the only Caucasian in the class, which made me stand out somewhat. Fantastic experience though.
I've advised others to train with O'ong in Bangkok. Sadly this is no longer an option.