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katago's aggression strategy http://www.lifein19x19.com/viewtopic.php?f=18&t=18485 |
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Author: | dhu163 [ Tue Nov 23, 2021 1:51 pm ] |
Post subject: | katago's aggression strategy |
I have been studying some opening principles for katago's aggression strategy (from very conservative to very aggressive). To me, the biggest change in strategy is how it deals with weak points and cutting points. And when splitting a side, the very conservative player will ensure life, playing away from living groups. When very conservative, they prioritise invading the opponent's moyos (approaching 3-4) and splitting their sides. When very aggressive, they slowly ensure they can prevent the opponent living easily in their area (including playing the bizzare looking 3-3 4-4 shimari), adding a move in the middle of their side and pincering any stone that approaches. This may sound contradictory but it really works. This principle also seems to apply to cross-cut fights. The conservative player will try to rescue all the stones, saying "let's all live, you can live with more points, I'll bribe you". In fact they tend to cut to sacrifice more often. Whereas the aggressive player will choose a thin line of cutting stones to either make a wall (with lots of cutting points) by double hanes (forcefully responding to all the opponent's key point moves) or anticipate severely attacking (or even capturing) one side or the other on a large scale. The aggressive player is very sensitive to how thick they are on the rest of the board even if it is over 5 stones away. The conservative player seems to focus on local profit. The aggressive player seems to view any side of the opponent that the opponent has played 3 moves on as small and says "I can still lean on that to build by own moyo" and after their own corners are defended, will be eager to play a very far extended moyo as long as they have many stones in that area (say six to zero) even if there are wide holes on the sides. This includes playing the 4-4, 7-3 shimari sometimes. In a fight where the stones are one on one, (or one on zero as mentioned above - preemptive defences), this is where the differences in strategy are most apparent. Balanced play tends to defend your own group first at the boundary of access to territory/eyespace/centre influence. Conservative will do so in a more defensive way - moving towards open space rather than obsessing over the corner mutual eyespace points. Aggressive will prefer to pincer and is less likely to tenuki unless it sets up a splitting attack - the attitude seems to be "this area is already mine if I add a move to attack, so I can't let you add another move to settle." If there is a fight where you have the advantage of 2 stones to 1 and you have to add another move to defend, then very aggressive tends to defend with the same move as the even player. 3 stones to 1 similarly - after all, you can't get around the fact you need the same 4 stones to capture a ponnuki, however much stronger you are than your opponent. However, I find that the conservative player often won't add another move to defend (because in order to be efficient and attack on a larger scale you tend to need to pincer and create another group that isn't connected to your original 2 stones) and will tenuki instead to live on the other side of the board. If there is a fight where you have the disadvantage of 1 stone to 3 or more, this is where it gets interesting. Conservative will play to reduce the area gradually from the outside by taking big points. Conservative seems more willing to attach to the opponent's stones in order to make shape now and probe. Aggressive will leave it for now but pre-emptively get solid in the area that the opponent will profit from an attack. Then it will mess around playing all sorts of loose shape points (3rd line splits under high stones) and eventually rescue a group deep in the opponent's moyo often making a large centre wall themselves, quickly living locally, or just creating aji in sente and playing tenuki. Aggressive knows there is only one area they need in order to profit and must keep aiming to seal off that area regardless of if there are cutting points or the opponent has space to live inside. However games between the balanced player seem to go on for a long time with a lot of tense probes and middling shapes - trying to defend slightly more efficiently but still leaving a cutting point. The timing of when the opponent exploits this and the direction they attack from is very complicated because the stones are somewhat tangled up and the opponent's stones can be vulnerable too. My feeling is that it is easier to learn strategies from the conservative or aggressive player since the balanced AI is just too complicated (pincer - counter-pincer and on and on). |
Author: | ez4u [ Sat Nov 27, 2021 12:34 am ] |
Post subject: | Re: katago's aggression strategy |
Very interesting! I assume you are doing this with "playoutDoublingAdvantage". What levels are you classifying as "very conservative" and "very aggressive"? |
Author: | Uberdude [ Sat Nov 27, 2021 10:21 am ] |
Post subject: | Re: katago's aggression strategy |
Daniel tried this out in the British Championship title match! My commentary (audio, so just the variations): |
Author: | kvasir [ Sat Nov 27, 2021 6:52 pm ] |
Post subject: | Re: katago's aggression strategy |
It would be nice if these ideas were illustrated with diagrams. It is already a bit clearer what was meant now that I have briefly browsed the SGF, It is interesting I'll try look at it closer later. |
Author: | dhu163 [ Wed Apr 27, 2022 8:22 am ] |
Post subject: | Re: katago's aggression strategy |
With either side, katago is confident of making life. So the main bonus that a stronger player has is noticing the subtle changes compared to "book positions" that affect status (life and death, ability to cut) many moves before needing to read it out. Logically, this seems to imply that strength helps most when optimising when one side is almost dead. Where should the attacker play to finish off the opponent, or a territory/moyo that still has aji. Is a solid kill better or a more ambitious claim better? When should the defender play activate the aji, and from which direction. Is it better to reduce on the outside first, or is it better to probe with the aji before deciding? What does this imply for how to play with each side? The conservative player should break up the board into lots of familiar little fights, preferring to settle large areas (get to endgame as quickly as possible, and avoid the middlegame). They say invade moyos at the last possible moment, but for conservative players, that moment comes earlier than most even if not even sente. In local fighting, if your group is alive, play more crude moves to settle the position locally and encourage the opponent to continue playing in that small area rather than making a moyo with their wall/influence. If you have the wall, balance avoiding being cut with trying to settle the position locally. Prefer shimaris that prioritise territory over influence. The aggressive player should invite the opponent into making a weak group in their area. Prepare to give way a little locally, just to ensure the opponent can't get eyespace in centre locally, then pincer stones that come near. If the opponent is forced to reduce lowly from further away, that remains just one weak stone and the position remains unsettled with many opportunities for them to make mistakes. If they don't enter your area, continue building it rather than invading the opponent's area, aiming to lean on their position severely for a double attack when they finally do enter your area. If you have a cutting point that can either lead to a fight (that you are confident in simply out of aggression) or the opponent can just simplify letting you connect, then try to make the opponent overconcentrated if the opponent simplifies, while still being able to handle the fight even when the opponent has more stones on that side. Sometimes the conservative player will do the same as a probe to decide whether to defend the cut, while the even player will leave it as a fight. Conservative: 4-4, cross fuseki, wedge safely in the opponent's moyo, gote (but at vital points) Aggressive: 3-4, 3-3, parallel fuseki, moyo, sente (if the opponent has to take a risk to respond) NB: some of this analysis was inspired by several pros saying something like "we see the AI line, and most of the time it makes sense and shows us clearly why a move is wrong, but the problem is that whatever line it shows us, we feel like this. Even if it showed us a crazy move, we would just nod along as AI is like God." This seems to call for more concrete analysis of what is going on, even if we can't fully appreciate pro reasoning, let alone AI, without a lot more experience. |
Author: | dhu163 [ Sat May 21, 2022 10:26 am ] |
Post subject: | Re: katago's aggression strategy |
A few more journalistic thoughts. Forcing moves: random or timesuji? Cross fuseki (fighting games) vs Parallel fuseki (moyo games) Play the same move when far ahead/behind but not in even game? local fighting choices Handicap games |
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