Blindfold Go on Ultra-Small Boards

by Richard Bozulich

© Copyright 2015 by Richard Bozulich

All rights reserved according to international law. No part of this work may be reproduced by any mechanical, photographic, or electronic process, nor may it be stored in a retrieval system, transmitted, or otherwise copied for public or private use without written permission from Kiseido Publishing Company.

Kiseido Publishing Company
Chigasaki, Japan

Another way to develop your ability to visualize positions on the go board is to play blindfold go on ultra-small boards, starting with a 2x2 board and working your way up, step by step, to a 5x5 board, then on to larger boards. Even if you don't use these boards to develop your visualization abilities, they might be a novel way to introduce go to beginners.

Go is usually played on a rectangular 19x19 grid, making up a grid of 361 playing points. In theory, go can be played on a board of any size. However, for ultra-small boards, such as a 2x2 board consisting of four playing points, territory in the usual sense doesn't arise. Games in which the struggle for territory arises becomes apparent in games played on 6x6-line boards. However, if the rules are slightly modified, interesting games can be played on boards with 2x2 to 5x5 lines. We will call games played on these ultra small boards Microgo.

The following are the rules for Microgo.

Rule 1. The game starts with an empty board.
Rule 2. A move is made by placing a stone on an intersection.
Rule 3. The player with the black stones moves first. The players then alternate in making their moves.
Rule 4. A player may not pass.
Rule 5. Once played, a stone stays in place; it can't move to another intersection.
Rule 6. A stone or a solidly connected group of stones of one color is captured and removed from the board if it does not have a liberty. Captured stones are not kept as prisoners.
Rule 7. Suicide is illegal. That is, unless you are making a capture, you may not place a stone on an intersection where it will not have a liberty.
Rule 8. No previous board position may be repeated.
Rule 9. The player who cannot make a legal move loses.

Rule 4 and Rule 9 are the only difference from the usual Japanese rules of go. One of the first things you might notice is that a game on a 1x1 board is trivial. Black immediately loses — because of Rules 4, 7, and 9, he doesn't have a legal move. However, a game on a 2x2 board is quite interesting because Rule 8 often comes into play. This is actually the ko rule, although, in the example that follows, a ko in the usual sense does not arise.

Figure 1

Dia. 1

Dia. 2
Because of the symmetry, it doesn't matter on which point Black plays his first move. If he starts with 1 in Figure 1, White has two possible answers, at 'a' and 'b'.

White 2 in Dia. 1 would be a mistake. Black would capture with 3. The result is shown in Dia. 2. White doesn't have a legal move, so he loses.

Figure 2

Figure 3

Figure 3a
Therefore, White answers Black 1 with 2 in Figure 2. Black responds with 3 in Figure 3 and White captures two stones with 4. Figure 3a shows the result. Black now has two possible moves. On the 1–2 point in the upper right corner or the 2–2 point in the lower right corner.

Dia. 3

Dia. 4

Dia. 5
Playing in the upper right corner with 5 in Dia. 3 is a mistake. White captures with 6 and the result is shown in Dia. 4. However, Black can't capture with 7 in Dia. 5, as this would result in the same position as in Figure 1, violating Rule 8.

Figure 4

Figure 4a

Figure 5
Instead of 5 in Dia. 3, Black must play 5 in Figure 4. White captures with 6 and the result is shown in Figure 4a. Black captures with 7 in Figure 5 and the result is shown in Figure 5a.

Figure 5a

Figure 6

Figure 7
White must now plays diagonally opposite the black stone with 8 in Figure 6. But, if Black plays 9 in Figure 7, White can't capture at 'a' as this would result in the same position as Figure 3 (or Figure 3a). The conclusion is that Black wins on a 2x2 board. As an exercise, determine what would happen if Black plays 9 at 'a'.

Go on a 3x3 Board
On a 3x3 board, Black will win if he plays correctly.

Figure 1

Figure 2

Figure 3
Starting on the central point with 1 in Figure 1 is the strongest move. Black now dominates the whole board.

Playing on a side with White 2 in Figure 2 is the strongest move. By playing on the opposite side with 3, Black will be able to make an eye no matter how White plays.

If White plays 4 in Figure 3, Black makes an eye with 5. If White plays 4 at 5, Black plays at 4. These two points are miai.

Dia. 1

Figure 4

Figure 4a
Connecting with White 6 in Dia. 1 loses immediately. After Black 7, White doesn't have a legal move, as playing at either 'a' or 'b' is suicide, violating Rule 7. Therefore, White must play at 6 in Figure 4, the only legal move. White captures with 7 and The result is shown in Figure 4a.

Dia. 2

Figure 5
White cannot recapture with 8 in Dia. 2, as this reverts to Figure 3, so he has to play 8 in Figure 5. However, after Black captures with 9, White doesn't have a legal move, so he loses.

Go on a 4x4 Board
Go on a 4x4 board becomes much more interesting. A possible strategy for White might be to play imitation go. Let's investigate this strategy.

Figure 1

Figure 2

Figure 3
Black 1 in Figure 1, or any of the second-line points, seems to be the best move. If White plays imitation go, the moves to White 8 can be expected. Ordinarily, it would be a draw, but in microgo, Black can't pass so he has to make a move. If Black plays 9 and 11 in Figure 2 and White continues to imitate Black's moves with 10 and 12. After 13, White can longer play symmetrically — he has to capture with 14. Black responds with 15 in Figure 3. White answers with 16 and Black captures with 17.
Next —

Figure 4

Figure 5

Figure 6
White 18 in Figure 4 is the only resistance. Black now ataries with 19 and White captures with 20. Black next ataries with 21 in Figure 5 and White captures with 22, but his group is still in atari, so Black captures with 23 in Figure 6.

Figure 6a

Figure 7
The result is shown in Figure 6a. White can't pass, so he continues with the moves from 24 to 32 (at 26) in Figure 7. After Black captures the stone at 26, White doesn't have a legal move, so he loses.

What happens if White stops playing imitation go after Black 9 in Figure 2 and plays 10 at 11?

Figure 8

Figure 9

Figure 9a
If White answer Black 9 with 10 in Figure 8, he wins the capturing race. After White captures with 14, Black's only legal move is to play 15, but White then captures Black with 16 in Figure 9. The result is shown in Figure 9a.

Figure 10

Figure 11

Figure 12
According to the rules, Black must continue playing with 17 to 21 in Figure 10, but, after White 22, he no longer has a legal move (Black 'a' would be suicide), so he loses.

Black must find a way to foil White's imitation strategy. One possibility is to answer White 2 with Black 3 in Figure 11. After the moves to 12, Black ataries with 13 in Figure 12. After White captures with 14 —

Figure 13

Figure 14
Black captures the white stones with 15 in Figure 13. The result is shown in Figure 14. White loses.

Figure 15

Figure 16

Figure 17
Figure 15 shows another game. After Black 5, White plays a hane with 6. After Black makes an eye with 9, White expands his eye space with 10 in Figure 16. Black peeps with 11, then captures a stone with 13. This is a ko, so White can't immediately recapture. In fact, he has only two legal moves: at 14 in Figure 17 or to capture a stone by playing 14 at 15. If he plays 14 in Figure 17, he loses immediately, but what happens if he captures a stone at 15?

Figure 15
If White captures the marked stone with 14, Black ends the ko by connecting with 15. That leaves 16 as White's only legal move. But Black can now win by playing on the marked stone, capturing all of White's stones.

There are a lot of possible games on a 4x4 board. With perfect play, the first move (Black) should always win, but there are a lot of places where either side can make a mistake, so it is an ideal arena for you and your go friends to practice playing blindfold go. When you have mastered go on this board, move on to a 5x5 board. If you start practicing blindfold go on boards 6x6 or larger, it is best to use the standard Japanese or Chinese rules of go.