Forum for Shusaku fuseki
Shusaku Fuseki and falling into disuse [#543]
From the main page: "The popularity of this opening pattern waned after the introduction of komi, since White was not as pressed to play aggressively."
I don't understand this. If this fuseki was an appropriate strategy without komi, why would this change after getting komi? An acceptable white strategy cannot be made worse by starting with free points.
That depends on what you mean by "acceptable". In no-komi Go White starts at a clear disadvantage. Therefore it was felt that White had to adapt a risky strategy by playing aggressively in an attempt to catch up. The introduction of komi was intended to bring the start of the game to a more balanced situation. White no longer has to take the same risks in order to overcome the initial disadvantage. This has impacted White's play. If you check any of the major databases, you will see that in pre-komi games White chose to play 
as an approach to the upper right corner by a wide margin. This allowed Black to continue with the Shusaku Fuseki. Following the introduction of komi, in the open corner became the most popular choice, greatly reducing Black's opportunities to play the Shusaki Fuseki or any similar variant.
While I started writing this, Dave posted the basic idea, so I'll delete my exposition (his is better), and just elaborate on what he said.
Using a toy model, imagine the following two strategies in the absence of komi: Strategy A gives white a 30% chance of winning by 10, a 30% chance of losing by 5 and a 40% chance of losing by 10. Komi changes little. Strategy B gives white a 25% chance of winning by 5, a 50% chance of losing by 5 and a 25% chance of losing by 10. Komi changes a great deal.
In the absence of komi, you'd prefer strategy A, because even though you lose big when you do lose, it provides the highest chance of winning (perhaps Strategy A often provokes a kill or be killed fight). But with komi, you might prefer a strategy that keeps most games close. This is roughly the idea of ARichManShouldNotPickQuarrels, and while that thought usually applies to the macroendgame or endgame, it does apply here.
Without compensation, White was pressed to play aggressively. With compensation she is not so anymore. She can focus more on stability and less on development. Likewise, Black must now emphasize development at the expense of stability, while before he could just rely on going first. The shift in emphasis for both will lead to different opening patterns.
I won't discuss the relative merits of the Shusaku Fuseki moves.
Remark: If Go were solved, this wouldn't be true: there would be one complete decision tree. There would be no strategies because the player to whose advantage the solution is, would know exactly what to do.
Players develop strategies in pursuit of victory. They influence each other.
Yes, but Black plays the Shusaku fuseki. Making that kosumi is Black's choice, and of course for the studious amateur that's why we have to make a keima today.
Bob McGuigan: I think the idea is that in no-komi go Black starts with an advantage and hence can safely play solid moves which do not put a lot of pressure on White, such as the Shusaku kosumi. When White has komi there is a feeling that the Shusaku-style fuseki doesn't put enough pressure on White, i.e. Black is making things a little too easy for White. I think these judgements are fairly subtle and, of course, there are pros who do play the Shusaku kosumi
Calvin: In Invincible: The Games of Shusaku and a few other sources, a fuseki is considered "Shusaku-style" with just 1-3-5. Certainly this is still played very often today, especially if you allow 
to be at hoshi. I was under the impression that the question of this being a potentially slow strategy for black really only arises at 
. Of course, the parent page includes , so I suppose the "disuse" comment is reasonable, although players as strong as Cho U, Hu Yaoyu, and have tried in touraments, too. It's just less popular.
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