Doshu Puzzle
Doshu Puzzle
Object: Make the yellow and red tokens swap places.
You can drag a token (keep the mouse key pressed) any distance in any of the four major directions, but you cannot move a piece by itself: you must always pull a second touching token (the dragged token's neighbor in the direction opposite the drag). If there is no adjacent token on the opposite side, a token cannot move.
The dragging token (together with the dragged token) can also move over (but not onto) non-empty positions, as long as the dragging and the dragged token both land on empty positions. Thus with yellow-red-yellow in a row, you can drag the red token two positions to the right to get yellow-yellow-red.
This "dragging" restriction makes even the most simple board setups (with six or eight pieces) a challenge.