RobertJasiek wrote:
You thought that the opening was about opening principles, such as how to reduce san-ren-sei? This is mostly far above what you need at your current level.
The law of seasonality: Why do red and yellow leaves appear in autumn and not in summer? Why are trees without leaves in the winter?
One should know what moves are appropriate for a given stage in the game. Playing endgame moves in the opening is bad and failing to efficiently strengthen groups in anticipation of middle game fighting is just as bad.
Different fusekis (which are prescribed whole-board lines of play, just as joseki are prescribed local lines of play) work in different ways. Sometimes there is no fuseki, but just one big fight that spills out all over the board, like one would see in some Huang Longshi games. The 3-rensei is a moyo-oriented fuseki, but weak players will often try to play a territory-oriented game on the basis of sanrensei. Might be better for one to learn komoku openings or just start a big fight somewhere in the board and learn how to profit from it so as to be in a favorable position for the middle game and endgame. Or even do the same after a sanrensei has been played, just to get acquainted with how this fuseki works.
A very radical explanation of opening play is that the main purpose of opening play is to claim the largest areas with the greatest potential for development while reducing the potential for development of enemy groups, which is why the corner areas are where the very first plays occur in a game; the geometry of the corner reduces the need for stones to surround territory. Sometimes one will see something like in the below game (So Yôkoku 9p as Black vs. Nakano Yasuhiro 9p as White in the 62nd NHK Cup), but this means trading the solidity of a corner position for the flexibility of a center-ward one.
https://www.youtube.com/watch?v=skkzt0KsevgAfter that, one seeks to claim key points and develop positions for future expansion and advantage in middle game fighting, and to make any urgent plays, as weak groups will have limited potential to support expansion unless their weakness is fixed in the first place. Not to mention that weak groups become the target of attack for stronger ones and such fights often help the attacking side secure additional territory. Corner approaches and
warikomi (wedge & split) plays are often useful to reduce the potential of a large section of the board becoming territory. To get to the point, let's just say that the goal of the opening is to develop a position favorable to effective fighting during the middle game, which will in turn influence the outcome of the endgame.
Tesuji must never be overlooked. These are important to play Go effectively and read out positions efficiently.
Quote:
Classic opening books are for single digit kyus or dans.
This presumes that the learner has been studying the way that has always been typical for serious students of Go in Japan. Lots of self-study through replaying games, doing tsumego, and reviewing games against other players.