Basic Sente and Gote on the Edge

Many times in GO, a shape will head toward the edge of the board, but stones will not be placed all the way to the edge of the board. Players feel that early in the game there are more important moves than sealing up the borders on the edge. But as the game moves toward the end, these borders generally get locked down. There is a pretty predictable set of moves to do this, but there is a little more going on than you might originally see.


Take a look at the diagram above. Black has claimed a corner, and assumes that he can make 2 eyes and live there. White has surrounded him. On the top right border (at T4 and T5) you see that both black and white extended their wall straight to the edge to determine the border. Although that can happen in a game, it usually doesn't. If we look at the bottom (at P1 and Q1) you can see that the border remains open.

Imagine white decides to settle this border and moves here first. Instead of playing straight down to P1, he squeezes black by taking Q1. This gives black one less open spot to build eyes with, and one less point when the score is counted at the end. Black can't respond with P1, because that would put P1 in atari right away. (A white stone at O1 would capture P1 immediately.) Black has to stop the white advance with R1, which puts white's Q1 in atari.

White needs to save Q1 from atari. P1 does the trick. Now white is solid and he stole a point from black. Should black be happy with this and play elsewhere? Unfortunately for black, there is still a threat by white.

The stone at R1 isn't strong enough to stop another attack by white! White places a stone at R2 and puts R1 in atari. How many more stones will black have to play to stop this attack? Black is not only losing points, he may lose this whole corner if he can't make 2 eyes!

Black must respond to this series of moves by playing at R2 to seal the border from further invasions, even though it costs him another point of territory. Replay almost any game and you will see this series of moves. Now you know how to squeeze 2 points out of your opponent on the edge, and what to do if they start to reduce your territory. If black had played here first, he could have played at P1 and pushed white the other way.

Is there anything more subtle going on? Yes. These moves act as a series - once one side starts them, the other "must" respond. (Obviously you don't have to, but it is a series of forced moves.) The person that starts the series has the advantage. Not only do they get to steal a few points from their opponent, they get to pick where the next battle will be after this little border series is finished. When you play, if you have the freedom to move where you want, and are causing your opponent to react to your moves, you have sente (Japanese word pronounced SEN-TAY). You are on offense and are forcing your opponent to react. If you are playing moves to counter threats from your opponent, especially moves that don't really help improve your position, you are in gote (GOH-TAY). The move by black at R2 to end the series above is a gote move. The first move of the series by white is a sente move.

Sente and gote are talked about a lot. They are particularly useful in battles over a ko (which I haven't talked about on this blog yet). In general, you should be trying to play moves that attack your opponent, grab more territory, and force them to react defensively. You want to have sente. The less your moves do to force your opponent to make a gote move, the more you open the door to letting them play a strong sente move that forces you back on the defensive.

Makes me think of a cool GO T-shirt: