In go, there has always been a big gap between genders. But that gap is narrowing all the time. Ten years ago, female go players had no chance of beating a top pro, but now, even titleholders are feeling the heat. A few weeks ago, Izumi Kobayashi, the female Honinbo titleholder, beat Naoki Hane, the male Tengen titleholder. China and South Korea are also seeing changes. Chinese player Rui Naiwei, who lives and competes in South Korea, is generally regarded as the strongest woman go player. Currently, 16 women--six from South Korea and five each from China and Japan--are battling to decide who is the strongest in the World Championship for Women.

Diagram 1: This is a game from the first round between Kobayashi (Black) and Rui. playing for South Korea.

Although the wariuchi of 7 is slightly unconventional, the moves through 17 do not arouse much comment. White 18 is a fighting move (see Reference 1 for the standard approach). White 20 prepares for a ko and after black 23 a ko is unavoidable.

Reference 1: When Black plays 1, White usually plays at 4 and 6. The moves through 9 follow naturally when the stone marked with a cross is at D. However, in this case, with that stone one space farther away, Black can play at A, threatening to cut at B next. Or if White plays at A, Black can still aim at invading at C. On top of that, the stone marked with the triangle has been cut off from the left corner and does not play a role anymore.

Diagram 2: White takes the ko with 24, but Black seems to almost shun the ko, and plays a very mild ko threat at 25. Since Black can invade here anyway, and since even after this move, Black is not threatened, White forces 26 for 27, then finishes the ko with 28 to capture both marked stones. Even though territorially Black seems to be doing OK, White has become very strong in the upper part of the board. Once the ko started, Black should have played a more forceful ko threat (see Reference 2). White 30 is an invitation to invade and Kobayashi obliges right away. As a result, White secures her lower left corner and builds even more influence in the center, while Black's invasion group is alive. This would not have been so bad, if Black did not have to connect in gote with 57.

Reference 2: (Black 5 and 11 take the ko at the marked stone, white 8 takes the ko at 2)

When White takes the ko with 2, Black should make a forceful ko threat with 3. If White captures the ko as in the game, Black gets a better result. If White answers with 4, Black captures the ko at the marked stone with 5. Black can now keep fighting with 7. With 8, White takes the ko, but black 9 poses another ko threat, to be answered with white 10. Black 11 captures the ko again and White has no ko threats, so once again he is forced to connect with 12. Next, black 13 gives her a good result. As long as the white stones in the upper left are not strong, Black's crossed stones are doing OK. Later, Black can live in the lower left with the sequence black A, white B, black C, white D and black E.

Problem 1: How should White respond to black 57 in Diagram 2? We will continue this game next week.

Handicap Go

In physics, every action causes an equal but opposite reaction. In go, an action that is very strong may provoke an equally strong reaction. Last week, we warned about the possible countereffectiveness of attachments. Let's look at a popular attachment and see what happens.

Diagram 3: In response to the marked white stone, black 1 is a strong attachment. White cannot resist with 2, because black 3 and 5 would follow. In some cases, White can set up a ladder, but in handicap games, with the marked stones in place and stones in all corners, all ladders are favorable for Black in the beginning.

Diagram 4: After black 1, White will usually play a hane with 2. The moves through 5 are one pattern. After white 6, black 7 is necessary to prevent the cut of white A, black B and white C. White has a couple of options for his next move, including 8, D and E. In spite of Black's seemingly tough play, White easily lives. And although the result to 7 is viewed as even locally, Black has not made good use of his marked stones.

Diagram 5: After black 3, White can also play at 4 and gain more corner territory. Black 5 and 7 create a lot of cutting points in White's shape, and after White reinforces with 8, Black forces 9 for 10, then builds influence with 11 and 13 (or A). White's group is alive, but through this way of playing, Black has established a framework that uses all of his marked stones.

Diagram 6: After white 2, Black can also block with 3. White will then play atari with 4, giving Black bad shape with 5--bad shape because now the moves 3, 5 and the marked stone form an empty triangle. After black 5, White has two cutting points. He can only cover one of them. His options for doing that range from A through C. But in this case, with the black handicap stones in place already, cutting at B seems to work well for Black. Therefore, White will probably play at B.

Problem 2: After black 3, white can also play at 4. How should Black respond?

Solution to last week's problem

The question was what would happen if White did not add a move in this situation. Black can invade at 1. If White resists with 2, Black cuts with 3. White can make a ko by playing 6 at A or 8 at A, but if he insists on trying to live without a ko, in the moves through 11, White dies. He can capture five stones with A, but Black plays where 11 used to be and kills the white stones.