Full Report for GoRoGo by Mitsuo Yamamoto

Full Report for GoRoGo by Mitsuo Yamamoto

Go with the addition of neutral Henge pieces.


GoRoGo is new Go variant game for two players played with each 10 ordinary black and white pieces and 5 additional neutral ones. Each player has two of the neutral pieces, and one starts on the game board.

Like Go, the game is played on a grid, but the board has only a 5x5 grid with 25 intersections and 40 paths. The purpose of the game is to obtain more of your opponent's pieces, not to claim an area majority.

Since there are only 25 pieces, the game is over after 24 moves at most. A player cannot pass, nor play a neutral piece last. If they don't have a legal move, they lose.

The neutral pieces are both black and white. That is, on Black's turn, a neutral piece is a black piece. Then on White's turn, it is a white piece. This allows moves that are normally prohibited in Go, such as 'Kou'. A player can attack into an area that in Go would be protected.

GoRoGo is a GO game but not GO. It means that the tactics are GO tactics but the strategy isn't GO.


General comments:

Play: Combinatorial

Family: Combinatorial 2016

Mechanism(s): Capture,Territory

Components: Board

BGG Stats

BGG EntryGoRoGo
BGG Rating6.65
BGG Weight0

BGG Ratings and Comments

hippiephysicschickN/AKs 2p abstract
mrraow7The neutral stones really do change the nature of the game, making it feel very different from go, and interesting on a small board; nonetheless, I suspect it has limited replay value.
Kaffedrake4A small claustrophobic tactical Go variant with neutral pieces. There are worse Go variants with neutral pieces.
GeekenN/A5.8KS 2020
lizlam9A fun and simple Go variant.
dwskoogN/ANumbered and signed mini board

Levels of Play

AIStrong WinsDrawsStrong Losses#GamesStrong Win%p1 Win%Game Length
Grand Unified UCT(U1-T,rSel=s, exp=0.70, secs=0.01)360036100.0055.5625.00
Grand Unified UCT(U1-T,rSel=s, exp=0.70, secs=0.03)36194679.3546.7425.00
Grand Unified UCT(U1-T,rSel=s, exp=0.70, secs=0.55)35223992.3146.1525.00

Level of Play: Strong beats Weak 60% of the time (lower bound with 90% confidence).

Draw%, p1 win% and game length may give some indication of trends as AI strength increases; but be aware that the AI can introduce bias due to horizon effects, poor heuristics, etc.

Kolomogorov Complexity Estimate

Size (bytes)24156
Reference Size10577

Ai Ai calculates the size of the implementation, and compares it to the Ai Ai implementation of the simplest possible game (which just fills the board). Note that this estimate may include some graphics and heuristics code as well as the game logic. See the wikipedia entry for more details.

Playout Complexity Estimate

Playouts per second61418.65 (16.28µs/playout)
Reference Size519049.10 (1.93µs/playout)
Ratio (low is good)8.45

Tavener complexity: the heat generated by playing every possible instance of a game with a perfectly efficient programme. Since this is not possible to calculate, Ai Ai calculates the number of random playouts per second and compares it to the fastest non-trivial Ai Ai game (Connect 4). This ratio gives a practical indication of how complex the game is. Combine this with the computational state space, and you can get an idea of how strong the default (MCTS-based) AI will be.

Win % By Player (Bias)

1: White win %39.58±2.49Includes draws = 50%
2: Black win %60.42±2.55Includes draws = 50%
Draw %10.73Percentage of games where all players draw.
Decisive %89.27Percentage of games with a single winner.
Samples1444Quantity of logged games played

Note: that win/loss statistics may vary depending on thinking time (horizon effect, etc.), bad heuristics, bugs, and other factors, so should be taken with a pinch of salt. (Given perfect play, any game of pure skill will always end in the same result.)

Note: Ai Ai differentiates between states where all players draw or win or lose; this is mostly to support cooperative games.

Mirroring Strategies

Rotation (Half turn) lost each game as expected.
Reflection (X axis) lost each game as expected.
Reflection (Y axis) lost each game as expected.
Copy last move lost each game as expected.

Mirroring strategies attempt to copy the previous move. On first move, they will attempt to play in the centre. If neither of these are possible, they will pick a random move. Each entry represents a different form of copying; direct copy, reflection in either the X or Y axis, half-turn rotation.


Game length25.00 
Branching factor21.83 
Complexity10^30.76Based on game length and branching factor
Samples1444Quantity of logged games played

Move Classification

Distinct actions51Number of distinct moves (e.g. "e4") regardless of position in game tree
Good moves23A good move is selected by the AI more than the average
Bad moves27A bad move is selected by the AI less than the average
Samples1444Quantity of logged games played

Change in Material Per Turn

This chart is based on a single playout, and gives a feel for the change in material over the course of a game.


This chart shows the best move value with respect to the active player; the orange line represents the value of doing nothing (null move).

The lead changed on 8% of the game turns. Ai Ai found 0 critical turns (turns with only one good option).

Overall, this playout was 68.00% hot.

Position Heatmap

This chart shows the relative temperature of all moves each turn. Colour range: black (worst), red, orange(even), yellow, white(best).


Table: branching factor per turn.

Action Types per Turn

This chart is based on a single playout, and gives a feel for the types of moves available over the course of a game.

Red: removal, Black: move, Blue: Add, Grey: pass, Purple: swap sides, Brown: other.

Positions Reachable at Depth (Includes Transpositions)


Note: most games do not take board rotation and reflection into consideration.
Multi-part turns could be treated as the same or different depth depending on the implementation.
Counts to depth N include all moves reachable at lower depths.
Zobrist hashes are not available for this game, so transpositions are included in the counts.

Shortest Game(s)

No solutions found to depth 4.





Black to win in 8 moves

White to win in 7 moves

White to win in 5 moves

White to win in 5 moves

White to win in 5 moves

White to win in 5 moves

Black to win in 4 moves

White to win in 7 moves

White to win in 7 moves

White to win in 5 moves

White to win in 5 moves

Black to win in 6 moves

Selection criteria: first move must be unique, and not forced to avoid losing. Beyond that, Puzzles will be rated by the product of [total move]/[best moves] at each step, and the best puzzles selected.