I'm a beginner but I've been learning music theory and practicing on a MIDI keyboard and FL Studio DAW. Just as I was learning basic chords and chord progressions in western music I was introduced to the Japanese In Sen scale, one of several pentatonic scales common in Japanese music. I quite enjoy it and writing little compositions in it, and as I've been listening to koto music I often hear them accompanying the main melody line with chords.
I want to learn about how to construct pleasant-sounding chords for such a scale with its wide intervals. In the western scales the chords and progressions that I've been learning are all diatonic for whatever scale I'm using. Should all the notes in the chords I use with the InSen scale come from that scale? Are there suggested formulas or sets of intervals that I can apply to creating chords in the InSen or other similar scales? Is there any concept of "leading chords" that applies to this kind of music?
NOTE: I may have the "In" and "In Sen" scales confused - in different texts I see the terms used a little differently, but the gist of the question remains - how to construct chords in pentatonic scales with wide/irregular intervals.