Verto

Reversi reworked

Material

• Square board (7 × 7 or 9 × 9 spaces)
• 49 (or 81) Reversi stones (one side light, other side dark)

The Verto board (7 × 7 shown). The lighter outer ring is the perimeter; the darker center is the interior.

Objective

Have the majority of stones on the interior of the board.

The perimeter — every edge and corner space — does not score. Stones standing there are worth nothing at the end of the game, even though they may still take part in captures.

Preparation

In the beginning the board is empty and the stones are put in reach for both players. The players choose their colors.

Light makes the first move then players take turns.

Play

In each turn a player enters one stone (own color up) on an empty space, either as a capture or as a quiet entry. If neither is possible the player passes.

Capture

If a stone is placed such that exactly one opponent stone is orthogonally or diagonally between the entered stone and another friendly stone, then this opponent stone is flipped and becomes a friendly stone. This is called a capture.

The entered stone must then be used as the starting point (the “anchor”) to capture another opponent stone, and so on, until no further capture is available.

Captured stones are flipped immediately after each step — not all together when the turn ends.

Light to move. Enter at d4 and flip c3, then must continue with d6, flipping d5. The move is written d4:c3,d6:d5.

After the chain: both stones were flipped immediately after each step.

A capture is similar to a capture in Checkers: like jumping over one opponent stone, but here no stone is moved and a captured stone is not removed (it is flipped instead).

Capturing is not mandatory. A player may instead make a quiet entry elsewhere. But once a capture is made, that capture and every capture that follows it must be made. However, it is not necessary to follow the path where a maximum of captures is possible.

One capture per entry. When several opponent stones could be flipped by the same entry, the player must choose one of them.

Light to move. Entering at d4 flips one of the three dark stones — d4:c4, d4:d3 or d4:d5. Capturing more than one stone at once is not allowed.

Perimeter-only captures are illegal

A capture uses three spaces in a row: the entered stone, the flipped opponent stone, and the friendly anchor stone.

If all three lie on the perimeter, the capture is not allowed. It may neither start a turn nor continue a capture chain — the chain simply stops before that step.

Either the entered stone or the anchor may sit on the perimeter. The capture is forbidden only when the whole sandwich stays on the perimeter (the flipped stone is on the perimeter as well). As soon as the sandwich reaches a single interior space, the capture is legal.

Light to move. a1:b2 is legal: the entered stone is on the corner, but the sandwich a1–b2–c3 reaches into the interior. The sandwich a1–b1–c1 lies solely on the perimeter and is not allowed.

Quiet entry

If no capture is available (or the player prefers not to capture), a single stone is entered on an empty interior space.

A quiet entry must obey all of the following:

1. Interior only. Stones may never be entered quietly on an edge or corner space.
2. Isolated or next to an enemy. The space must either be isolated (no adjacent stone at all) or lie next to an enemy stone (orthogonally or diagonally). A quiet entry beside only friendly stones is not allowed.

Light to move. Light may capture with g5:f5, or enter quietly next to the enemy at e4, e6, f4 or f6, or far away (b2, f2, … — isolated). d4, d5 and d6 touch only the friendly e5 — neither isolated nor next to an enemy — and are illegal. No quiet entry is legal on the perimeter.

Pass

If a player can neither capture nor make a legal quiet entry, the player must pass. This includes the case where no empty legal space remains.

End of the game

The game ends when both players pass consecutively.

Only interior stones score. The player with the majority of interior stones wins.

End of a game — Light wins 15–10. The interior is filled; g1, a7 and g7 stay empty because no capture reaches them and quiet entry is forbidden on the perimeter. Both players pass and the game ends. Perimeter stones are ignored when scoring.

Verto is played on a 7 × 7 (standard) or a 9 × 9 board. Both interiors hold an odd number of spaces (25 or 49), so a draw is impossible.