Nine Men's Morris on Board Atlas: mills, the swing mill, and flying at three
A practical guide to the Board Atlas Nine Men's Morris table as checked on 7 October 2026: mills during placement, protected pieces, the swing mill that removes a piece every move, flying at three, blockade wins, and where the game comes from.
Nine Men's Morris comes down to one habit: before every move, look for the point where a piece would complete a line of three — yours or your opponent's. Each completed line, a mill, removes an enemy piece. Reduce your opponent to two pieces, or leave them with no legal move, and you win. Everything else in the rules is about when and where those mills can happen.
This guide covers the Nine Men's Morris table on Board Atlas as its rules text and game logic read on 7 October 2026. Morris is played with several local variations; this is about ours.
What this version actually does
The table's rules text says: each player places nine pieces, then moves one piece along a line to a neighbouring empty point; forming a mill removes an opposing piece outside a mill, or any piece if all are protected; with three pieces a player may fly to any empty point; reduce the opponent below three pieces or leave them without a legal move to win. Reading the game logic on the same day adds the details in the right-hand column.
| Rule | Board Atlas Nine Men's Morris (checked 7 Oct 2026) |
|---|---|
| Board | 24 points on three nested squares joined at the mid-points; 16 possible mills, all straight lines — no diagonals |
| Pieces | Nine each, placed one per turn onto any empty point |
| Mills while placing | Count. A mill made during placement removes a piece, just like later |
| Moving | After your nine are placed, move one piece along a line to an adjacent empty point |
| Removal | One opposing piece not in a mill; if every opposing piece is in a mill, any piece |
| Two mills at once | Still one removal |
| Re-forming a mill | Moving a piece out of a mill and back in counts as a new mill |
| Flying | With exactly three pieces left, after placement, a piece may move to any empty point |
| Win | Opponent has fewer than three pieces, or no legal move — checked once both players have placed all nine |
The rules text lists no draw rule. The lobby offers 2, 3 or 5 minutes per move, a practice bot, and friend rooms with a room code.
A map you can talk about
The table does not need coordinates, but they help when you describe a position. The usual labels run a–g left to right and 1–7 bottom to top:
- Outer square: a1, d1, g1, g4, g7, d7, a7, a4
- Middle square: b2, d2, f2, f4, f6, d6, b6, b4
- Inner square: c3, d3, e3, e4, e5, d5, c5, c4
The 16 mills are the twelve sides of the three squares (e.g. a1–d1–g1, b2–b4–b6) plus the four cross-lines cut in half: d1–d2–d3, d5–d6–d7, a4–b4–c4 and e4–f4–g4. Note that d1–d2–d3 is a mill, but d3–d5 is not connected through the centre — there is no centre point.
The placement phase is not a warm-up
New players often treat the first eighteen turns as setup. On this table they are not: a mill made while placing removes a piece immediately. Two consequences:
- Every placement is a threat check. If your opponent has two pieces on a line with the third point empty, block it now or lose a piece.
- Spread out. Wikipedia's summary of strategy advice is that early on it matters more to place pieces in versatile spots than to chase an early mill and bunch up in one area. The four mid-points of the middle square — b4, d2, f4, d6 — each have four neighbours, the most of any point, so a piece there is the hardest to trap. Corners have only two.
Movement does not start until you have placed all nine. Pieces stuck in a cluster at that moment may have nowhere to go.
The swing mill: one piece, a removal every move
Because re-forming a mill counts, the strongest pattern in the game is a piece that shuttles between two mills.
Example. You hold a1, a7, b2 and b6, and a fifth piece on a4.
- a1–a4–a7 is already a mill.
- Move a4 → b4. That completes b2–b4–b6 — remove one of their pieces.
- Move b4 → a4. That completes a1–a4–a7 again — remove another.
- Repeat while both points stay free.
Your opponent can only stop it by getting a piece onto the empty point. In this example a4's neighbours are a1, a7 and b4 — all yours — so while you sit on b4 they cannot walk into a4 at all. Their only way in is to step onto b4 from c4 while you sit on a4, or to fly once they are down to three. Wikipedia's strategy section makes the same point: practical winning chances arise when a single piece shuttles between two distinct mills. The defensive lesson is the same pattern in reverse: if your opponent builds two lines that share a swing point, occupy that point first.
If one of their pieces can close a mill on every move, you are already behind. Block the swing point, not the mill that is currently closed.
Which piece to remove
When you make a mill you choose the victim, but pieces inside the opponent's mills are protected while any other piece is available. Good default choices (editorial, not rules):
- A piece that is one move from closing a mill of its own.
- A piece that blocks one of your open lines.
- A piece that would become their swing piece.
Taking the nearest piece without looking at these is the most common way to win a piece and lose the position.
Flying at three pieces
When a player is down to exactly three, their pieces may jump to any empty point. Two things change:
- The defender gets slippery. A flying piece can block any open mill on the board, not just a neighbouring one.
- The attacker needs two threats. Against a flyer, one open mill is always blockable. Set up two lines that each need one more piece, so one block cannot cover both.
Flying is not universal. Wikipedia notes that some rule books treat it as the standard game, some as a variation, and some leave it out; a 19th-century manual called it the "truly rustic mode of playing the game". Board Atlas plays with flying.
Winning by blockade
The other way to win is to leave your opponent no legal move. On this table it is checked once both players have placed all nine, so a crowded board right after placement can end the game at once. If you are the one getting crowded, keep at least one piece next to an empty point.
Where the game comes from
Nine Men's Morris is old; Wikipedia says it dates back at least to the Roman Empire. Earlier claims are disputed: R. C. Bell dated boards cut into the temple roof at Kurna in Egypt to around 1400 BCE, while Friedrich Berger argued the diagrams "cannot be dated". Wikipedia says it peaked in popularity in medieval England, where giant outdoor boards were sometimes cut into village greens — the kind Shakespeare's Titania means in A Midsummer Night's Dream when she complains that "The nine men's morris is filled up with mud". The word "morris" is usually traced to the Latin merellus, a counter or gaming piece, rather than to morris dancing.
In 1996 Ralph Gasser published "Solving Nine Men's Morris": with perfect play from both sides, the game is a draw. Neither player at an online table plays perfectly, which is why the swing mill still wins games.
Quick checklist
- Mills while placing count — block every two-in-a-row
- Spread out; b4, d2, f4, d6 have the most neighbours
- Re-forming a mill removes again — build a swing mill, block theirs
- Remove the piece that threatens, not the nearest one
- At three pieces a player flies — attack with two threats
- Fewer than three pieces, or no legal move, loses
Sources & checks
How we write and check articles: Editorial method