Last week, I wrote about Cho Chikun’s introductory book on go. One of the lessons I found very useful in the said book was that a one-space jump on the fourth line and the two-space jump on the third is always connected.
1 on 4
When moving along the fourth line, a one-space jump is a more efficient and solid move than a solid extension. The two stones moves faster while staying connected. However, are these stones really connected? Here is the proof.
The cut at of 1 is White’s best attempt to cut the two Black stones. However, this is futile.
When the opponent tries to cut a one-space jump on the fourth line, one should block underneath, i.e. block near the edge not from the center, such as Black 2, if one wants to stay connected.
The sequence from 3 to 9 should follow naturally. White’s two stones on the second line are dead because it only has two liberties (another concept worth remembering). Black has nothing to worry about the cut at x because White cannot start a ladder with White x.
2 on 3
A two-space jump on the third line is the simplest way to establish a base. Many standard sequences uses this jump to stabilize a group. Stones also move faster with the two-space jump while keeping groups connected.
So, why are the two stones connected? What if the opponent tries to cut the two-space jump on the third line, e.g. Black 1 against the two White stones?
Again, the proper defensive move is the block underneath, White 2 in the diagram.
Since Black wants to severe the White stones, Black will next hane on White 2.
White’s only reply is to atari against Black 1. After this, Black’s attempt to cut White will end in death for the cutting stone, Black 3.
Black has no choice but to follow the sequence up to White 8. Note that the Black stones on the second line only have two liberties, thus these stones are dead as is. White also has the beginnings to secure two eyes even if Black gets the opportunity to deprive White a path to the centre.
A bit of caution to the beginner: 1 on 4, and 2 on 3, and the accompanying tactics to keep these stones connected, apply only as is. If there are stones surrounding the group, make sure to read out the possible continuations and its variations before deciding if the group are indeed connected. Also, 1 on 4 and 2 on 3 may not be the most efficient moves in a game. However, one can still gain much knowing these two basic stone movement.