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[go]$$B Big points
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$$ | . . . . . . . . . . . . . 7 . . b . . |
$$ | . . . 2 . . . . . , . . . . . 1 . . . |
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$$ | . . . . . . . . . . . . . . . . 6 . . |
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$$ | . . . 4 . . . . . , . . . 5 . , 3 . . |
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$$ ---------------------------------------[/go]
Let's take this starting position, assuming the open corners are always the biggest points, i.e. the next major area. For the sake of the argument, I have played

on a 3-4 point, creating an asymmetric position.
According to dwyrin's heuristic, the bottom area is now the biggest area, because

and

are separated by 12 open spaces, while all the other sides are 11 spaces wide.
Another heuristic says that asymmetric corner stones invite enclosures or approaches. Today, a high 2-space enclosure is more popular.

takes a big point.
The bottom has now become the smallest area, the others still being 11 points wide. Conventional wisdom says that an enclosure invites an extension. Hence, a White splitting move at ''a'' is a traditional big point, perhaps the biggest point. However, modern play suggests that an approach from the inside is better, because corners are more important than sides, and bot play suggests that White even jumps into the corner with ''b''.
According to the strict definition of wide spaces, the 3-3 invasion is not "big", but we can extend the definition with such available invasion points.

creates an "urgent" situation for Black, whose corner stone is threatened to be pincered, so that it can't make a base (borrowed, implicit definition of "urgent")
Now the question is if

finds itself in an urgent position? It can still be sacrificed with a corner invasion, or extend along the side, unless Black kicks it and attacks next, creating a double purpose move. Is playing elsewhere worth all that?
- Click Here To Show Diagram Code
[go]$$W Big points
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . X . . X O . |
$$ | . . . O . . . . . , . . . . . X O O . |
$$ | . . . . . . . . . . . . . . . X X O . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 1 . . |
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$$ | . . 2 . . . . . . . . . . . . . . . . |
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$$ | . . . O . . . . . , . . . X . , X . . |
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$$ ---------------------------------------[/go]
Let's assume White chooses the modern bot corner pattern, finishing it with

, an "urgent" point. Temperature has dropped in the area and Black can look for a big point. The widest area is now on the left. Although LZ slightly prefers to approach from the top or the bottom, when fed the approach from the wider side, she doesn't heavily object
- Click Here To Show Diagram Code
[go]$$W Big points
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . 6 . . 2 . . . . . . . X . . X O . |
$$ | . . . O . . . . . , . . . . . X O O . |
$$ | . . . . . . . . . . . . . . . X X O . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . 1 . . . . . . . . . . . . . a . . |
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$$ | . . 3 . . . . . . . . . . . . . . . . |
$$ | . O . . . . . . . . . . . . . . . . . |
$$ | . X X X . 4 . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . X X O . . . 5 . , . . . X . , X . . |
$$ | . X O . . O . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
A variation of the same corner pattern gives this result. Black is not stable yet, so, rather than playing a big point at the top, White applies pressure with the leisurely

With that extension in place, Black surely wants to approach from the top? Not really: LZ has her eye on the forcing move ''a'', which is not traditional. Her next choice is to invade the corner.
If we insist playing the approach at

, LZ finds value in connecting her forcing move with her side extension, increasing the pressure on Black's lower left group. Both

and

are "urgent", next Black invades at

because White has left the corner unattended and a double approach makes less sense due to White's stones on the side.
We can say this invasion is now a genuine "big point".
- Click Here To Show Diagram Code
[go]$$W Big points
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . X 1 . X . . . . . . . X . . X O . |
$$ | . . 2 O . . . . . 0 . . . . . X O O . |
$$ | . . . 3 . . . . . . . . . . . X X O . |
$$ | . 4 6 7 . . . . . . . . . . . . O . . |
$$ | . 8 5 9 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . O . . . . . . . . . . . . . b . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . O . . . . . . . . . . . . . . . . . |
$$ | . X X X . X . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . X X O . . . O . , . . . X . , X . . |
$$ | . X O . . O . . . . . a . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
After the corner pattern in the top left, Black plays the big point at the top and White does likewise at the bottom with ''a''.
The right side is the only remaining major area. LZ still wants to play ''b'' and it seems to make a big difference (10%) with any other move in that area. This suggests ''b'' is not so much a "big point" but one that raises the temperature, creating an "urgent" situation for White.
- Click Here To Show Diagram Code
[go]$$W Big points
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . X O . X . . . . . . . X . . X O . |
$$ | . . X O . . . . . X . . . . . X O O . |
$$ | . . . O . . . . . . . . . . . X X O . |
$$ | . X X O . . . . . . . . . . . 3 O . . |
$$ | . X O O . . . . . . . . . . . . . 6 . |
$$ | . . . . . . . . . . . . . . . 2 O . . |
$$ | . . O . . . . . . . . . . . . 4 1 . . |
$$ | . . . , . . . . . , . . . . . , 5 . . |
$$ | . . . . . . . . . . . . . . 7 . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . O . . . . . . . . . . . . . . . . . |
$$ | . X X X . X . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . X X O . . . O . , . . . X . , X . . |
$$ | . X O . . O . . . . . O . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
The difference is too big to ignore, so let's take LZ's suggestion.
With some goodwill,

is the last big point, although we should perhaps say that the right side was the last major area and Black developed it with

through

while putting pressure on White.
%%%%
In the above analysis, we have switched between the heuristic of playing a big point and LZ's top choice. We chose a big point when LZ only marginally objected (<2%). When LZ's top choice was considerably better, we followed her, which was particularly true for the "urgent" points.
In this example it was Black who took the last big point. However it was not the fact that Black claimed the last major area but the way he did, with that pressuring sequence, which made him stay in the game (at 47%).