Nine men's morris problem #521

The task

To move

Light

Difficulty

Medium

Goal

mill in 3

All men are on the board and the game is in the movement phase: Light has 7, Dark has 6. A medium problem: three turns, and the opponent may close a mill of his own along the way. Check what each of his replies does before you commit.

What to look for

• Movement phase: men only step to neighbouring points, so check which of them are actually free.
• The opponent may strike back with a mill of his own; your line has to survive that.

How the answer is checked

There is exactly one first move that forces the result; any other first move allows the defence to escape. Moves that keep the forced result are accepted later in the line, and a move that loses it is taken back with a short note.