Figure 1 In this 2004 AGA-Ing Pro Cup match between Huiren Yang 1P (White) and Mingjiu Jiang 7P (Black), B31 has capped White’s weak 3- stone W12-20 group, blocking its easy path into the center. Although Black has no reasonable expectation of killing these stones, this is nevertheless the best way to exploit their weakness, aiming to profit elsewhere by harassing them. |
Figure 2 This is how the game actually continued. (The details of the complex tactics involved are far beyond our present interest, and so will not be discussed here.) White resigned after B159 because the impenetrable Black lower center moyo is just too large for White to overcome. |
Figure 3 in this 2005 North American Masters match between Jie Li 9D (White) and Thomas Hsiang 7D (Black), Black has just erred with B81. Instead, he should have secured his large weak group via the one point skip to “a”. Now White can exploit this oversight - but how? |
Diagram 1 Capping with W1 seems like the logical move, but here it’s not best because it leads to a Ko which might involve dangerous complications. Instead, 9D Li thought through those complications, and came up with an even better idea. |
Diagram 2 Instead of capping, the diagonal move of W1 here is even better, because it precludes that Ko possibility. Next, Black thought it prudent to strengthen (and expand) his corner with B2 before answering W1. Unfortunately that turned out badly because B2 induced W3, which then contributed importantly to White’s attack on the weak Black group below. After the B2, W3 exchange, Black had time to attach with B4, and at that point he must have believed that he was going to survive White’s attack relatively unscathed. But that expectation was dashed when the peep of W13 and the following W15 set up the later cut of W21, trapping the 8 Blacks on the right and leaving the rest of the big weak Black group fleeing with only 1 eye. Only a few moves later Black was forced to resign. |
Diagram 3 In this 2006 Paris Open Championship Tournament game between Motoki Noguchi 7P (White) and Fan Hui 2P (Black), B79 (B1 here) was played to make it difficult for White’s two marked stones to safely connect to his friendly stones in the upper left. This put the onus on White to either break through Black’s encirclement - highly unlikely in this position - or to make life in this immediate area in the face of Black’s surrounding strength. |
Diagram 4 As this game developed, instead of trying too hard to enclose and kill the weak White center group, Black instead wisely chose to make profit at the top without unduly strengthening the target group. This succeeded so well that White resigned before the weak group’s ultimate fate could even be decided! This was superb strategy, and exemplifies how such an exploitation should ideally be carried out. |
Diagram 5 In this game between a 2D and 3D, Black has suffered a huge loss of 8 stones in the lower left, so his only possible chance to win is if he can somehow mange to kill the large still eyeless marked White group in the upper center. Since this group’s only realistic chance to connect with friendly stones is with the Whites in the lower right, the attachment of B1 is a fine (and typical) way for Black to try to prevent that connection. Although that strategy didn’t succeed in this game, it in no way detracts from the general principle involved. |
Diagram 6 In this game between two 4D’s, when W1 invades Black’s thin lower right position, with White’s strength on both the bottom left and right side to run to, it would seem that this stone is not only quite safe, but actually may be stronger than the lone Black to its left as well. But is it really? Black’s clever response gives the answer. |
Diagram 7 After the twin kikashis of B2 and 4 followed by the attachment of B6, the lone White stone has now become weak and can only run straight up into the center, where Black is already strong. The price that Black has had to pay for this is that W3 and 5 have given White a considerable profit on the right, but if Black’s following center attack succeeds (as it did in this game), his compensation there will more than make up for that loss. So this strategy is inherently dangerous, but can be very effective if adequately followed up. |
Diagram 8 In this game between two 4D’s, White’s large weak center group offers Black an ideal opportunity to begin the creation of a large Moyo in Sente by forcing White to move in a desired direction. Do you see how? |
Diagram 9 B1 blocks White’s progress to the right, forcing his group to flee up into the open top, allowing B3 to begin sketching out a large moyo on the right side. Although this area is still much too large and open to all become territory, it does provide Black with considerable potential. How much of that potential territory can later be realized as solid territory is, of course, still to be determined in subsequent play, but it does provide Black with a significant winning chance. |
Diagram 10 In this position from a game between two 5D’s, Black has set White up for the devastating splitting attack of B1, which is also on the key shape point of the lower White group. |
Diagram 11 The choice and timing of the best splitting point and the ultimate outcome of the resulting fight are both a function of the opponents’ skills, but unless gross blunders occur the end result should more often than not be favorable to the attacking player. |
Figure 4 In this position W1 is the most logical (but hardly the only) way for White to play, making the fullest possible use of his upper left 4-4 point stone by making a long strategic extension from it. A squeeze play is the best way for Black to answer because Black is concerned with neutralizing White’s center thickness below, and B2 is the strongest and most aggressive pincer available. Perhaps most important, it encloses W1 tightly within Black Sector Lines, so it’s Sente! If instead Black were to passively extend at “a” to coordinate with his strong position in the lower right, W“b” would work much too well with both the White upper left star point stone and his thickness below for Black to allow. |
Diagram 12 If W3 now dives into the 3-3 point to seize the corner as shown here, this Joseki will inevitably follow, and that would leave Black with both thickness which helps neutralize White’s thickness below,
and Sente with which to play at either “a” or “b”in the upper left corner, again with a result White felt was unfavorable to him. So instead ... |
Diagram 13 The one point center skip of W3 to break the Black Sector Line was necessary if White didn’t want to become enclosed, and that was the first key move in his strategy. It also enclosed both the Black corner stone and B2 in White’s own fairly distant Sector Lines. Most important, it was Sente because a following move at 4 would force Black into a low, nearly enclosed position in the upper right corner. So... |
Diagram 14 Becoming enclosed would force the White stones to either live small in Gote or die, so escaping is essential. This one point skip of W9 is the best way to do that, because it retains Sente by threatening to continue at 10, which would force Black into a low position on the right edge. B10 Prevents White’s good move at this same point and increases Black’s potential right side territory, while aiming toward making that territory really huge if he can further coordinate it with his strong lower right corner. But despite that it’s Gote because it makes no serious enclosure threat against the W1-9 group. (W9 already broke what would have been Black’s new Sector Line.) |
Diagram 15 B“a” now to further expand his right side is both large and feasible, but then W14 will follow and that would be bad (although not disastrous) for the weak Black 3 stone string of one point skips! So instead ... B14 offers the weak Black string the most future alternatives, so it’s safest. But either B“c” or 15 is also feasible, with the choice between these options more a matter of the player’s judgment than of necessity. W15 was the key turning point in this part of the game! Unfortunately, it was somewhat overambitious, despite being the most consistent with White’s moyo strategy in playing W7 and 11. It mistakenly emphasized the creation of White’s potential upper left moyo over the safety of his weak stones on the right, and thereby violated the earlier noted key principle of: “Urgent Moves Before Big Moves”. |