To a beginner, the 19x19 board looks huge. Where to play? How to choose from 361 possibilities? Open in the corner. Sure. Which one? Where? Is it important?
It helps to know that there are only four points on the whole board where even games actually start [1] most of the time. They are named points in the upper right corner.
Four named points
Most (99% ?) of the first moves, , are made on these four named starting points. They also have systematic names derived from the linenumbers, but so does e.g. the 7-9 point, which is hardly ever played as a first move.
The second, third and fourth move may be a first move in another corner as well. But a local answer is also possible, as is (for the third and fourth move) a local reinforcement. Consequently those first moves in the corner can be made later. However,
Table of contents | Table of diagrams Four named points Starting points Corner joseki komoku kakari hoshi kakari |
Assuming most players adhere to the etiquette most of the time, these four points in the upper right corner are the starting points on the board:
In handicap games all four corners may already be occupied by the handicap stones. If so, white mostly plays a low approach, or (less frequently, even if it is possible) immediately takes a side by playing at 3-10 or 4-10. Sometimes even if there is an empty corner left to play in, white starts with this low approach.
When you are playing white in an even game and when you are playing black in a handicap game, your first move is the second move of the game. In an even game, most second moves are in an empty corner, too.
There may be an empty corner left, and it is possible to play in the middle of a side of the board, e.g. sanrensei. Anyway a second move in a corner will be made now or soon. Reinforcing a friendly stone is done with an enclosure (shimari). An approach to a single hostile stone in the corner is called kakari.
Corner joseki
Even further into the game the number of actually played moves is limited. Focus on what happens in one corner obviously blurs whole board vision, but the benefit is that it postpones the combinatorial explosion a little. The patterns of play that emerge have been studied for ages. The sequences of best moves for both (josekis), starting at komoku and at hoshi are the most relevant, and in both cases the low (see: board geography) kakari is played most often:
Joseki show actual moves. The fuseki exercises for beginners give a good indication of the reasoning applied to these moves. Looking at the types, or intended function of the first moves in the corner just a few sequences emerge.
corner -
kakari or tenuki
For the question which joseki choice is best, considering the rest of the board see Pages that urgently need to be written by people who know a lot more than I do? and joseki context.
[1] This is what I was looking for when I first clicked Starting points.