David, it's quite simple. Although my interest (at the moment) differ from Alan's in that I very much like some Sumatran and Peninsular Keris forms, for Nogo blades I am only into something, of which this one is a perfect example - Central Javanese, second part of 17th cent., high point of Kinatah work:
http://www.hermitagemuseum.org/wps/p...c+armor/515178
Later Nogo blade forms, even Javanese ones, are not my cup of tee.