I found the rules on wikipedia: http://en.wikipedia.org/wiki/Rock-paper-scissors
While reading, I came across the reference to the Japanese version called Jan-ken-pon.
My mind flashed-back to my childhood when my mom and I would play the "Rock, Paper,Scissors" derivative Jack en poy; the chant clearly going through my head "Jack en Poy. Hali Hali Hoy!" or "Pik, Pik... Papel, Gunting, Bato!" Surely, this had to be related to the Japanese version.
I looked up the rules of Jan-ken-pon: http://en.wikipedia.org/wiki/Jan-ken-pon
Sure enough, it was:
In the Philippines, a variation called jack en poy is used. This was introduced most likely during the Japanese occupation during World War II. The complete chant in Tagalog is Jack en poy, hali hali hoy, sino ang matalo, siya ang unggoy! ("Jack en poy, hali hali hoy, the one who loses is a monkey!"). Another variation is called bato bato pik! or simply pik.