Thanks for the input, everybody. "Guest" was right about the 5th fret. It's not a regular chord, but it does sound bluesy.

The other techniques don't seem to apply to my dulcimer. I checked against my Korg tuner, and pressing the string away from the fret doesn't produce the half-step. The note is merely a tiny bit lower than it should be. (This is with a noter.)

Wesley, I have experimented with slide dulcimer, using a small piece of clear plastic tubing. It works, but for me it's merely a novelty. I don't much care for notes that slide at anytime.

My method of play is to use a thumbpick for the melody string and pluck the others with my bare fingers. Sometimes I brush them or use "the dreaded bum-diddy strum."

Lin, I will look for Dead Willie Blues.