I'm wondering about what exactly fighting spirit is in the context of go.
If you think there is some value in what I am saying here, feel free to share it in go teaching sessions.
Here is some analysis of an unusual joseki.
- Click Here To Show Diagram Code
[go]$$c B
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . 0 . . . . 7 . |
$$ | . . . . . . . . . . . . 9 Q O 1 3 4 . |
$$ | . . . , . . . . . , . . . X X O 2 5 . |
$$ | . . . . . . . . . . . . . . . X 6 8 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]
- Click Here To Show Diagram Code
[go]$$c B
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . 3 O . 5 . . X . |
$$ | . . . . . . . . . . . 2 X O O X X O . |
$$ | . . . 6 . . . . . , . . 1 X X O O X 4 |
$$ | . . . . . . . . . . . . . . . X O O . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]
Why does a pushing move such as the marked move in the first diagram turn into such a mess of dead and intangled stones?
Some relevant points without certain conclusion (as is normally the case in the opening of Go).
1. Black has a cutting point with a weak shape initially (remember influence is often a weak group).
2. White has a valuable move at R16 that they should really have played instead of the marked move.
3. The marked move pushes at black's weaknesses when black has the first move in the corner.
4. We can call the marked move heavy since it is a weak stone trying to get extra endgame by pushing at black's weaknesses when the whole group hasn't played a proper move to defend the cutting point yet. Sometimes this is reasonable but only if the opponent's stones are weak enough that you can handle your own weaknesses.
5. This is fighting spirit. If I play the big R16 move myself, that is possible but I then have to deal with the big N16 (hane at the head of two stones) and R15 (serious cutting point) which is awkward. But if I don't play R16 and just defend with say N16, then white can play R16 and get a very large corner. However, black can cut Q17 due to all the space in the corner and weak points of both W chains. This is serious because if black captures either chain it is very big profit. If Q16 dies, then black not only deals with the big R16 move but directly captures from inside white's area. If P17 dies then the marked move becomes silly.
6. Without the marked move, black couldn't seriously cut P17 since white would go from very weak locally to not only having the R16 move but also lots of forcing moves on the corner.
7. The reason such a mess occurs is because after white responds at R16, the black corner stones are very weak and white can exploit them to escape with the key R16 group. However, that means white's S17 isn't connected and gets sacrificed. After this, black is alive in the corner and white can't easily fight on the outside so black spends two moves taking the key points N17 and N16 both taking a hane at the head of two stones and preventing white's move. At this point, the fight has mostly died down with the aji having settled so that white has some half-dead stones at the top, a more alive group on the right and black has quite a few liberties and local space on the outside. W M17 is a tight move that exploit's black's lack of liberties in the corner (white P18 is half sente on the corner) while also shorting liberties of black's centre group. Such a boundary point is very big since white's follow up at M16 seriously cramps black's centre group. So black cuts to settle the position, trying to capture the cutting stones and white sacrifices the stones for big moves and sente.
You might like to compare this position.
- Click Here To Show Diagram Code
[go]$$c B
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . 4 . . . . . . |
$$ | . . . . . . . . . . . . . . O O . . . |
$$ | . . . 2 . . . . . , . . 1 . X O . . . |
$$ | . . . . . . . . . . . . . . X X . 3 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]
In this situation, both sides have played more solidly. However, this tends to mean the groups are slow and have left a lot of space undefended. The corner is relatively much smaller since W is more solid in the corner with good control over the R16 point to the extent that W's follow up needs to push out more with R15, but that leaves an exploitable cutting point so isn't the biggest yet in the opening.
Why is
![black 1 :b1:](./images/smilies/b1.gif)
so big? Even after
![white 4 :w4:](./images/smilies/w4.gif)
, white still has a cutting point and B has the aji to seal W in with M18 (though B definitely needs a support move first in this position given W's support in the upper left). Note that whenever there is a weak group or unresolved fight, including over a wall, it is bigger to play living stones nearer that area (rather than say in the lower left corner).
W's shape means they have good control over P18, so that with another move at N17, they can get out and greatly reduce black. Similarly, B's shape means they have good control over O16, O15 etc. so another move makes a difference. Since both groups are fairly alive, any connected stone is alive, so dominating the width of the area they can escape by greatly affects their influence.
Probably B's main problem is not being alive so this the best move locally to deal with that. The main weakness is at O16 but for white to exploit that they would need O17 first (or N17 but that would be a weak stone). However W O17 is overly solid shape when W is already solid in the corner and W already has good control of P18 (it is like playing an empty triangle), so B isn't very worried about the weakness being exploited yet.
They must play at the right level, and not extend too far or too close. This can be tricky since there is a lot of space and hence possibilities in that area. For example black playing N17 leaves a serious cutting point at O16 which white can immediately counter with R15 to live (O16 then puts black's liberties at a worryingly low 3).
![black 3 :b3:](./images/smilies/b3.gif)
is also an interesting shape. Probably at R15 would be more secure for liberties, but the benefit of N16 is that black has miai of O16 and O15 and hence has plenty of liberties. The jump gets more shape towards the corner with more threatening attacks, though leaving the weakness is risky. Black's main threat is S17 next (black blocking with M18 is possible now) and the control S15 adds to T15 makes a noticeable difference to the connection (the variation if white tries S18 or R16). Sometimes black will have the support to go all the way to R18 (though normally white S17 will refute that).
Black's plan in the area is to say that white is solid but there is still quite a lot of points and eyespace in the corner and if I take them, then your group is weak, low and doesn't have many places to go even if it tries. In terms of shape, the goal is to reduce until white's only attacking move in the area is the empty triangle R16. (although that is inefficient, black does still need some thought to defend against it).
20220520 edit