Last week, we concluded the  sanrensei fuseki section of our Basic Opening Series.
This week, we will look at the principle ‘don’t play against stones to attack them’. Doesn’t that smell of a paradox? If you want to capture one stone or more stones, of course you have to take away liberties. So this principle of not attaching against a stone you try to capture sounds like a Catch-22.
Have you ever tried to capture a fish with your bare hands? Well, I have and I can tell you it isn’t easy. They are extremely agile and slippery. Even if you are convinced you got it and there is no escape, they worm their way out. I am not even talking about the wrong type of fish that may actually fight back and bite off a finger or two.
Of course, you know how to solve the problem above. You would use a fishing rod with bait, a fishing net , or lay a kind of trap. The most efficient trap is a drag net, a type of indirect net. So it turns out that a direct method is the least effective while a round-about strategy holds more promise. The same is true in go. Let’s investigate.
Diagram 1
Diagram 1
In this case, White has four liberties, i.e. the locations indicated by the triangles.
So what happens if Black tries to get hold of this White stone by occupying one of these locations?
Diagram 2
Diagram 2
As you can see, for the duration of Black’s move, White’s liberties are down to three. However, as soon as White plays his move, he has not four but five liberties (the marked locations). So, in spite of taking away one of White’s liberties, when the dust settles, it appears that Black increased White’s liberties by one. So the opposite of the intended goal was reached. Black attacked and made White stronger. In addition, as a side effect, Black 1 has only three liberties. Normally, a single Black stone would have four liberties, so in a way, Black has weakened himself. On top of that, White has five liberties against three of Black. So Black is not only strengthening White’s stone, he is decreasing the effectiveness of his own stone.
Diagram 3
Diagram 3
In an actual game, however, it is far more likely White will play a hane – I recommend White play hane at the top as the move of choice in reply to an attachment. As you can see for yourself, Black 1 has only two liberties (at B) while the original White stone has three (at A). Again, it seems the attacker is about to become the prey.
Problem 1
Problem 1
As you could see in the above diagrams, often it is not a good idea to try to capture a stone by taking away its liberties. The marked White stone is a pivotal stone as it splits Black’s stones. Therefore it is vital for Black to capture it. Where should Black play to capture the marked White stone?
Show Solution
Solution 1
Solution 1
Black 1 throws the perfect net. White’s marked stone cannot escape. If White tries with a move at 2, he is stopped in his tracks by Black 3.
Problem 2
Problem 2
Again the marked White stones constitute pivotal stones as they split Black’s groups. If Black does not capture these two stones, his own stones will most likely die. How can Black capture the marked White stones?
Show Solution
Solution 2
Solution 2
When you understand Solution 1, you can see the similarities with this problem. Again Black throws a net, this time a little wider. Whatever he tries, White cannot get out. For example, playing at 2 will not work. Black will just block White’s escape route with 3. Try out White’s other possible escape routes and verify for yourself Black can stop White from running out each time.
Problem 3
Problem 3(1-74)
This is a game between two top pros. A few interesting things happen for our study of nets. The first situation is when Black plays at 17 and White counters with 18 and 20. Finally, White throws a net around 17 by playing at 28. At the same time, Black attacks White’s stones at 2 and 22 from afar with 29 and tightens the net with 45 and 47. White’s two stones are lost. But what we are really interested in is the lower right corner. After White makes his corner alive with 74, Black’s groups are split by White’s three stones 58, 68, and 72.
Without thinking too deeply about the problem and without trying to read out all the variations, what is your first impulse for Black’s next move?
Show Solution
Solution 3
Solution 3
If you came up with 75 as Black’s next move, you were right. If White tries to run out with A, Black can just give way B, and after White C, Black D is correct. After that resistance is useless.
Reference 1
Reference 1(76-87)
The moves through 87 are given for reference. White understood he could not pull his stones out so he did the sensible thing – he sacrificed them on as small a scale as possible by forcing the sequence 76 through 83, then reinforcing his stones in sente with 84 through 87.
As you see, nets can be an effective means of surrounding a stone or a group of stones. Of course, this does not mean nets are always the correct way of capturing a stone. In fact, a stone that is already weak can often be captured by taking away a liberty. However, when attacking a group, doing this from a distance often works better.
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