Many months later as I sit here today, I recognized that no book by me on 9x9 Go is getting written unless I sketch it out here first. Consider this a lesson series on setting up winning positions on the 9x9 board. If you can do this well, you may find a great many transferrable skills to boost your 19x19 game too.
Lesson 1: Attach and pull back
We start from the popular “Three in a Row” opening. This opening typically follows the order given, but you can also reach it by the sequence 3-2-1 without misplaying. The knight’s move to 4 then is the most common response. Some people first attach at H5 as a probing move. The intention is to choose the preferred knight’s move for move 6 once symmetry is broken. In truth, White can play either way. The probe reflects strategic thinking but is tactically no better than playing the knight’s move first.
The maneuver of 5 and 7 is our focus here. It is called “attach and pull back” (or tsuki hiki, in Japanese). It is typically contrasted with “attach and extend” (tsuke nobi), in which move 7 is at C7. But that is a common misplay here.
Suppose Black plays move 7 at C7 to carry out the attach and extend maneuver. White pokes a vital point with 8. And unless Black wants to make an empty triangle, move 9 is inevitable. White can then jump to 10 without worry and secure an advantage in territory, once komi is factored in. Black can’t disconnect 10 through moves 11 to 15 because White can cut it at A.
Even if the cut at A above didn’t work well, White still has an amazing tactic: move 16 here. It threatens to link under at H5. If Black wants to prevent this by kicking at 17, White can springboard to another vital point at 18 and threaten to cut the knight’s move that the attach and extend maneuver had left behind. If Black had attached and simply pulled back afterward, this cutting weakness would not have lingered. The term for this in both English and Japanese is aji. On the 9x9 board, as on the 19x19 board, it is often best to minimize aji and connect solidly in positions like these.
Suppose again that Black understands this lesson and pulls back for move 7. I strongly suspect (having conducted only medium-depth AI analysis) that move 8 now becomes an inaccurate play for White. Although the same general tactic is conceivable for White, the lack of a cutting weakness in the black stones means that Black need not spend a move defending the cut. Instead, Black may attack straight away with move 17. The white stones in the upper right can no longer survive, so long as Black keeps playing accurately. And that last part is important. It’s not enough to attain a winning position if you let your guard down later on. The 9x9 board demands just as much focus to win at the higher ranks as the 19x19 board does, if not more so.
Please comment below if the topic suits you. And see you all the next time.