How to play

Move the tower

1. Choose a pillar to pick up its top ring.
2. Choose another pillar. It must be empty or have a larger ring on top.
3. Move one ring at a time. Put all rings on pillar C to win.

Choose a challenge

Start with three rings. Five sizes, from three to seven, are available. The fewest moves for a fresh tower are 2 to the power of the ring count, minus 1: 7, 15, 31, 63 or 127.

Undo and hints

Undo reverses one move. Hint selects a top ring and marks its next destination on a shortest legal route from the current tower; you still choose that destination. Escape or choosing the same pillar clears a selection.

After completion, Next tower starts the next size. Play again restarts the current size. Starting another unfinished tower asks before replacing its moves. Best scores stay saved.

Keyboard

Use 1, 2 and 3 for pillars A, B and C. Or Tab to a pillar, use left/right arrows to choose, and Enter or Space to select. Home and End choose A and C. Escape clears the selected ring.

Rule references: Math Is Fun: Tower of Hanoi; Carnegie Mellon: Towers of Hanoi recursion.