British Go Journal No. 12.  August 1970. Page 10.
There are numerous volumes in Japanese on opening theory, and the very amount of this information often puts the beginner off studying openings at all. The result is that quite moderate players are content to play very badly in the opening stage, particularly in even games, thinking that they cannot make any improvements at all without long study. In fact, a little study can bring benefit, if general principles are learnt. In this article I shall try to show how openings can be dealt with by exactly the same methods as are used in other stages of the game, provided that the special demands of the opening are known and kept in mind.
The opening is not a separate ritual, with its own rules; it is an integral part of the game, and so the same thought processes must be used to decide which moves to play as in the rest of the game. Like other parts of the game, the opening has its own demands, which alter slightly the importance of the conflicting aims of the player. You are trying to achieve the same things in the opening as later, but some will be of more importance later, and some of less.
Every beginner knows the paramount importance of the life and death of groups of stones, and moderate players recognise that the life of a large group is nearly always the first consideration in a fight. The life and death consideration is also very important in the opening stage, but in a rather subtle way. On the relatively clear board, it is nearly impossible to kill any particular group of stones, as the group has plenty of room to run away or to make its own basis for life independently. But the fact that attacks have to be answered or the group sacriiced can make these attacks profitable even when there is no hope of actually killing the group. It is possible, for instance, to make territory while retaining the initiative. If the territory-making moves are also threats on the life of a weak group.
So we see that the importance of this consideration in the opening is not so much in the actual killing of groups, as in the possibilities of making serious attacks on them. This is why professional players nearly always use pincer joseki, which prevent the attacking stone from forming a safe foundation too easily, and so open the way for attacks on it. The best strategy is therefore to keep your own groups strong (and your opponents groups weak) wherever possible, so that you and not he will have the opportunity of making profitable attacks. One way of doing this is by connecting your groups, and separating your opponents, and chances of so doing should be seized.
But the opening differs from other phases of the game because at this stage not too great an investment of stones has gone into any particular group, so that sacrificing it will not be so great a loss. Also the stones will not be totally lost, since at this fluid stage of the game compensating gains are fairly easily contrived.
In the latter stages there is little striving for influence - positions are well established by this time. But in the opening this aspect is of vital importance. The importance of influence is not so much that it can be turned into territory but that your opponent is forced to prevent you from doing so, thus giving you the opportunity of attacking his invading group.
Influence is usually formed only in exchange for other advantages - often the formation of territory by your opponent. The vital point is to strike a correct balance. The formation of territory in the opening is of course an advantage, since it is by territory that the game will eventually be decided, but at this stage territory should be lightly sketched out rather than solidly walled in.
The end game is concerned with small scale defence and reduction of already established areas, and the middle game with the life and death of groups and large scale formation and elimination of territory, but the opening, as we have seen above, is concerned not only with life and death but also with territory and influence. Not all of these things can be achieved at once, unless your opponent is generous, and the skill of opening play lies in firstly not being generous and secondly in balancing the conflicting aims. The Go proverb says "Avoid overconcentration", and this is usually taken to mean avoiding concentrating on one part of the board at the expense of the rest. While this is important, you should also avoid concentrating on one strategic aim at the expense of the others. For example, it is no use sketching out vast territories if your groups are so weak that your opponent can easily invade by threatening their lives; or to make your groups so safe that your opponent can make secure his large territory.
So now we know the theory of opening play - or at least the beginnings of it. How can this knowledge be translated into stones on the board? How, in the complicated posiions that arise in real games, can we find the moves that will achieve the objectives we want in the right order of priority?