British Go Journal No. 63. November 1984. Page 4.
Black: Nicola Oswald, 9k
White: Jonathon Ridgeway, 6k
The game-file in SGF format, without comments.
There are precisely four functions that a stone can serve:
(i) it can help to make territory,
(ii) it can prevent the opponent from making territory,
(iii) it can help to capture enemy stones,
(iv) it can help to prevent your stones from being captured.
Dia 1 ||
Dia 2 |
In every game of Go, positions roughly equivalent to Dia 1 arise. White has stones facing the edge of the board, which serve functions (i) and (iv) very effectively but are unlikely to be much use for (ii) and (iii). Black has outward facing stones which are generally useful in serving all four functions. This general usefulness is usually referred to as "influence".
When the stones are placed as in Dia 1, the territory White has gained is considered roughly equal in value to Black's influence. This equivalence depends on Black's ability eventually to make his stones serve one of the four functions mentioned. Black should not build influence if it can serve none of these functions, nor should he make the mistake of assuming in advance that it is destined to serve one particular function, especially number (i).
If the stones are placed as in Dia 2, the general usefulness or influence is virtually the same as in Dia 1, but the white stones surround 50% more territory. Black should only build influence on the fifth line from the edge when special strategic factors warrant it.
Dia 3 (1-57) |
This is why Nicola Oswald (9 kyu) should not have played moves 17 and 19 in Dia 3 in her game with Jonathon Ridgeway (6 kyu) in the Under 18 tournament on 13th October, reported elsewhere. The influence of these stones is not as valuable as white's large secure corner territory. Extending back to 29 with 17' is a better idea. If there had already been a black stone in that area, 17 and 19 might be worth considering as a strategy.
Incidentally, 11 is a rather strange move as well. If there were a white stone at A then 11 would protect the cut at B. But there isn't and it doesn't, and would have been better played at or near 37.
After white 22 it is already hard to see what useful function 17 and 19 are going to serve.
With the sequence from 25 - 35 Black builds some quite strong influence in exchange for allowing White a very secure position on the side with a small allowance of territory. How does she plan to make use of this influence?
Black's eyes should be fixed on the loose white framework on the left. Her influence provides an ideal background for an invasion, at C for example, or at D, followed by F if white replies at E.
There are two probable results to such an invasion. Black may live along the edge, in which case White will end up with influence of his own. But Black's already existing influence is ready to neutralise its effect, be it any of the four functions.
The other, more probable result, is that we end with black and white groups runnng rightwards across the board, in which case the black influence is ready to serve functions (iii) and (iv).
With 36 - 51 White builds a little influence of his own and presses down Black's upper edge territory. Unfortunately for him black 35, which at the time it was played was a rather slow move, ends up well placed to nullify this influence.
46 is a poor move, making the empty triangle; it should be at 48. Luckily for White, Black follows with an equally poor move at 47, which should be at G.
From moves 21 to 57, both players have been missing a vital good shape move. Can you spot it before looking at Dia 4?
Dia 4 (58-78) |
Black 21' should have been at 58 - this is always the vital point in the shape formed by moves 16 - 20. Playing here has precedence over all the subsequent manoeuvres carried out by both players.
Black 63 is a good move locally - it is usually good to prevent a group from being completely shut in against the edge, even when, as here, it can easily make two eys. But after 64 the last chance for Black to invade the left side has gone. The options for making use of her right side influence are now reduced to function (i).
With 69 - 78 Black is at it again, exchanging secure white territory for strong black influence which she has little use for.
Dia 5 Final position |
If you compare Dia 4 with the game's final position shown in Dia 5 you will see that Black's chickens have come home to roost. White has consolidated two large territories that Black encouraged him to make, while Black has been compelled to use her influence only for function (i) - and territory in the centre of the board is notoriously easy to reduce in the end game.
White won by 22 points, which is what he ought to have done considering he is three stones stronger. Despite losing this game, Nicola Oswald did well enough to become the first British Under 14 Go Champion, and incidentally the first female chanpion in the Association's history.