In games with experienced go players ...
By Rob Van Zeijst
In games with experienced go players, some novices are able to keep their groups alive and even stay ahead on points until the endgame. Then suddenly their territories seem to shrink while those of their opponents expand. The bad news is that less experienced players could lose 20 to 30 points in the endgame. The good news is they can do something about it. Not being a computer, a novice will find it extremely difficult to play an endgame like a professional. A computer, however, can beat a pro in the endgame because it can calculate a number of different outcomes instantaneously. We might not become that good, but study, discipline and practice will help close the gap.
Diagram 1: Black 1 is a strong move. What will happen if White ignores this move?
Diagram 2: With the marked stone in place, Black can strike with the oki-tesuji, or placement tesuji, at 1. White has to connect at 2, then reinforce with 4 and 6 before playing at 8 to make sure his stones stay alive. However, his two marked stones have weakened while Black's marked stone has become stronger. This is not so good for White.
Reference 1: In response to black 1, what about white 2? Black will just push through with 3. The best White can do is squeeze with the combination 4 through 10.
Reference 2: But Black connects with 11 after White's last move (at A). White can now live in sente with the combination of 12 through 16 but Black's thickness is huge. Black's marked stone is now part of a solid wall with White's marked stones helplessly clinging to it. Black can play B or C in sente. It is safe to say White has lost this game.
Reference 3: That is the reason White will usually answer black 1 with 2. Even if Black answers with 3, White is safe. In regard to the sequence black A, white B, black C and white D, Black cannot play at E as this puts his own stone in atari. Instead of 2, White can also defend by playing at D (gote, but stylish) or at F (blunt but sente), as Black will usually answer at 3.
Solutions to last week's problems
Solution 1A and 1B: White 1 is a strong move. Black has no choice but to connect with 2, but this allows White to connect underneath with 3 and 5. Throwing in with 6 is clever as it makes 8 sente, as well as 10 in Solution 1B. White must connect with 9 and 11. Black's life-saving moves are 12 and 14, but it leaves him with only 2 points of territory.
Solution 2: As stated last week, white 1 and 3, played in order to switch to 5 and 7, is a bad strategy. White 5 was aiming at a placement at A, but after defending with 6, Black can turn the tables with B. Black took advantage of this mistake with the placement at 8. White has no choice but to play 9 through 19. Black then switched to 20 to attack White's marked stones. What is going on? If during the attack, Black gets a few stones in the center, e.g. around C and D, he can next play at E, which kills the entire white group on the right (there is no eye around F). In other words, after the sequence 8 through 19, White's stones are very weak, leaving him unable to fight in the center. Needless to say, Black won this game easily.
Reference 4: In Solution 2, White wanted to play at 2, but Black could have countered with the sequence through 9, bottling up the marked white stone. White has to live with A, followed by black B, white C. But then black D virtually kills the white stones at lower right.
Problems
Problem 1: Black 1 is an oki-tesuji aimed at reducing White's territory. White 2 is a mistake. Where should Black play next?
Problem 2: How can Black use an oki-tesuji to reduce White's territory in sente?
Problem 3: The territories on the upper right are not completely finished. If it is White's turn, he can decide this part in sente by playing at A, followed by black B, white C and black D. However, if it is Black's turn, he has a great oki-tesuji to avoid this. Where should Black play?
Want to find out more? Come to Ben's Cafe in Takadanobaba, Tokyo (03-3202-2445), where the English speaking go community congregates every Sunday. You can enjoy free lessons, 11 a.m.-1 p.m. Ben's Cafe can be accessed at www.benscafe.com.
Van Zeijst is a four-time European go champion and European representative at the Fujitsu World Championship.