Life-and-Death problems in real games
When we play Go games on the Internet or read the played games, we often encounter life-and-death problems in the games. If the problems have stable boundary, they usually can be analyzed by XuanXuanGo's problem solver to find the best solutions. Followings are some examples showing you the skills and methods to use XuanXuanGo to analyze the problems. If you're watching other's games playing on the Internet, you can use the function of getting the board-status from other program's window or Clipboard to import the board status of the games you're watching, then you can start the analysis process for the problems in the games.
This is a game played by two professional Go players, there is a capture-race in the lower-left corner. After white played at A in the real game, black resigns. To analyze the problem, we need just encircle the problem with "Selection" marks, as shown in above figure. Please be noted, the marks should FULLY encircle the problem region, so there is a mark on the left side line even without a stone there. The fully encircled marks help XuanXuanGo exclude the stones outside the marked region, it doesn't mean that XuanXuanGo only solve fully enclosed problems. After the problem region is defined, please make sure the side next to move is correct, you can change it by right-clicking on the board. After we press "Solve" button, the solver engine moves at A, just like the real game played, the conclusion is white wins the capture-race. When the solver engine is activated, we can go back to the initial problem status and move outside the marked region, then the solver will treat the human's move as tenuki and try to move for black. The solver moves at A too, the conclusion is black has a Ko in sente.
Time used to solve the problem: 1.95 Sec.
This is a real game I played on the Internet. The game result depends on the capture-race at the center of the board. To analyze the problem, I add two white stones on the upper left corner of the problem, because XuanXuanGo will not be able to figure out the problem area if a two-space opening exists. On the upper right corner of the problem, I added a black stone, as the bamboo connection is solid, adding a stone to connect it to outer stones will make the analyzing process much faster. After I mark the problem as above, I press "Solve" button, the result is a Seki inside. Considering it's very hard for the upper black stones that participate the capture-race to live inside the white's area, the ultimate result should be white wins. But in the real game, white played very badly and result in a Ko in black's favor inside and resigned soon. Time used to solve the problem: 14.47 Sec.
This is also a real game I played on the Internet. Have the six marked stones the chance to revive? After I encircle the problem area with "Selection" marks, I add several black stones. I do so in order to connect the black stones at the corner with the outer stones, this will speed up the analyzing process considerably. Otherwise, there will be much more empty points inside the problem, the solving process would be much longer. The analyzing process is very fast, it takes only 1.2 second to get the result: black can have a Ko to revive. Although the Ko is in white's favor, but it's much better than being captured for nothing. The first two moves are obvious, the third move is critical.
Time used to solve the problem: 1.2 Sec.
I saw this problem on a Go forum, somebody were discussing the life-and-death on the lower right corner. To verify the move played at real game, I used the function Getting the board-status from other program's window or Clipboard to import the board status from the web browser, then I marked the problem area before I started the problem solving process. It takes 4.5 seconds to find the right solution. Did you know where white played to save his endangered stones? Time used to solve the problem: 4.5 Sec.
