Phantom Go

    Keywords: Variant

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A snapback is captured and re-captured

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Overview

Phantom Go is a variant of Go for two players and a referee. The players only see their own stones, but they don't know where the opponent plays. The referee sees the moves of both players and takes care that they only play legal moves.

Rules

Each player has his own board, set up so that the opponent cannot see it. The referee has a board of his own on which he plays the moves of both players. He can see both player's boards.

To make a move, a player plays a stone on his own board. The referee then checks on his board whether the move is legal and informs both players about the tried move. How exactly the refereee comments on the move depends on the rule variant (see below).

As long as a player tries to play an illegal move (such as on a nonempty intersection, or suicide, or capturing back a ko), it's still his turn and he may try another move. After the player has made a legal move, the referee copies the move to his own board. Then, it's the other player's turn.

Phantom go is usually played on a 9×9 or 13×13 board.

Common Referee Rules

The referee answers each try with one of the following comments:

  • Black/White has moved, White/Black to play.
  • Black/White puts White/Black [optionally: and himself] into atari.
    Only if the stones were not in atari before the move.
  • Black/White has captured the following stones.
    After which he points out exactly which stones were captured to both players.
    If a move both captures and puts some stones into atari, the referee says both.
  • Illegal move.
  • Black/White passes.

The referee does NOT say:

  • Which stones have been put into atari.
  • Which stones are still in atari.
  • Which stones are no longer in atari.
  • For what reason the move was illegal (such as a stone already being present, or suicide, or ko).

Example

[Diagram]

A snapback is captured and re-captured


A snapback sounds like this:

B1: Black puts a white group into atari.
W2: White has played, Black to play.
B3: Black captures the stone at a and puts White and himself into atari.
W4: White captures the 3 stones at b, c and d.

Hamburg Referee Rules

The referee answers each try with one of the following comments:

  • Black/White has moved, White/Black to move.
  • Black/White [optionally: captures n stones and] puts White/Black [optionally: and himself] into atari.
  • There is already an opponent’s stone.
  • There is already an own stone.
  • Suicide.
  • The ko cannot be captured back immediately.
  • Black/White passes.

The referee does NOT say:

  • Which of the stones have been put into atari.
  • How many stones have been put into atari.
  • Which stones are no longer in atari.
  • Which of the stones have been captured.

Miscellaneous

Phantom Go needs a lot of physical space since the players sit back-to-back and the referee stands between them. Each of the three needs a table with a board, stones and bowls.

There is an Android app called [ext] Phantom Go that allows two players to play Phantom Go using a single phone or tablet. The app takes the role of the referee.

See also


Phantom Go last edited by RolandIllig on September 24, 2022 - 21:20
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