A simple technique for creating doubles with one hand.
The bachi is held so that the stick can lie flat on the drum face; the kind of grip one might use for side-stick on the snare. With the butt of the bachi remaining on the skin, the hand slaps the bachi down flat with each stroke. The wrist/palm remains on the skin. By moving the arm position so that the bachi overhangs the edge of the drum, the butt of the bachi lifts when the bachi makes the downward strike. The bachi teeters over the edge. The second strike occurs as the hand raises and the butt of the bachi returns to the skin.