> Thanks for an excellent description of "the nakade > problem." I've found that it is easy for a "5kyu KGS > player" - myself - to exploit such situations. I can't > escape observing that endgame moves where a bot > permits me to take a yose point here, another there, > all the while drawing closer to a mythical 0.5 win in > it's mind, lead to the position where a miscalculation > about a group puts the program inescapably behind. > How do you know this is really happening? Do you have access to what the program is thinking? Could it be possible that the program knows it is lost the whole time? That's what it seems like to me from your description. Unless you calculated the exact score considering the nakade you can't really know that this is what happened.
If you have access to the program logs, you would know, but I would be willing to bet that if you think that is what is going on, the program probably is lost and knows it - because you would get the same behavior. At the very least you wouldn't be able to tell either way. To get the evil nakade behavior, you have to have several events conspire to make this happen. You have to have a nakade pattern on the board somewhere, the score has to be close and in your favor considering the nakade, and the program has to believe that it is more advantageous to give away stones that not. Despite what many people believe, MC programs don't normally believe it's better to win small and they are not hell-bent on giving away stones in order to try to make the score come out to be exactly 0.5 win. Although it's easy to see that nakade is a problem, I agree with someone who said it takes a lot of skill to produce this. In fact, I believe that it cannot be done reliably by any player unless he is already much stronger than the program, in which case he doesn't "need" to do it in order to beat the program. (Indeed, it may be a counterproductive strategy if it distracts you from playing good moves.) Most MC programs won't just let you pick off points because that is normally a strategy that decreases your winning chances. They will only do that if every move leads to the same win or loss in every single play-out, or if the small win turns out to be easier to manage. I have to believe that this is not in general a "technique" to be used to consistently beat a MC program, it is more a tool of opportunity - you can probably set it up if everything is just right to begin with and/or the program stumbles into in more or less on it's own and loses because of it. I would love to see a 5kyu player get on KGS and beat mogo in more than 1 out of 10 games using this specific strategy. My guess is that if your energy is spent setting up this trick, you will play weaker in general. - Don > My hypothesis is that the computer is thinking the > group has a greater than 50% chance of living, but > this is true only if the computer plays a vital point > and/or the opponent fails to take that point. In > those cases, all playouts lead to a win for the > computer. But anyone about 8-10kyu is likely to spot > the vital point and take it, leading to a 100% loss > for the computer. > > >From observation, mid kyu players will set up these > situations and slay the computer with a high degree of > probability - say 80%. > >> A 4-6 kyu human is behind by 10-15 points in the >> midgame (at that stage the >> probability of winning is correlated with territory, >> so the MC bot is >> building fine.) He creates a 12-16 point worth >> nakade trick in a corner >> and does not solve it.The bot is happy, it thinks a >> bulk five is alive or >> something like that. Perhaps the human sacrificed >> another 15 points >> somewhere to create the trick so he should be dead >> lost. But, he only >> has to play on, reduce, etc. As the endgame >> approaches, the MC bot >> allows the reduction only until the territorial >> balance would change the >> winner. The player is happy, he turned a 25 points >> loss into a 1.5 point >> loss (assumed by the program) and has a 12 point >> surprise. >> At the end, when the whole board is decided, the >> player kills >> the bot's group and the bot turns a sure win into a >> sure loss and resigns. >> >> Because the trick can only be played by similar >> strength players (much >> weaker players can't build something like that, much >> stronger don't need >> it) >> it affects the rating of the bots. I guess >> CrazyStone could be near KGS >> 1dan >> with that solved. It is 2k now. But, of course, the >> solution may not >> come at >> the price of making the program weaker. That is the >> difficult part. >> > > > Terry McIntyre <[EMAIL PROTECTED]> > > “Wherever is found what is called a paternal government, there is found state > education. It has been discovered that the best way to insure implicit > obedience is to commence tyranny in the nursery.” > > Benjamin Disraeli, Speech in the House of Commons [June 15, 1874] > > > > ____________________________________________________________________________________ > Never miss a thing. Make Yahoo your home page. > http://www.yahoo.com/r/hs > _______________________________________________ > computer-go mailing list > computer-go@computer-go.org > http://www.computer-go.org/mailman/listinfo/computer-go/ > > _______________________________________________ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
