Usually I don't comment on the opening, since the game is nearly always decided later and also Bill is usually sooner and always better at commenting it. I want to make an exception because the position at 28 is strikingly out of balance. Compare Black's stones, what they are doing and how they are doing it, with White's stones. The Black stones tell a much clearer story.
$$ Position at move 28
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . O . . . . . . O X . . . |
$$ | . . . O . . . . . X . O . . . , X . . |
$$ | . . . . . . O . X . . . . . . X . . . |
$$ | . . O . . . . . . . . O . . . . . . . |
$$ | . . . . . . . . X . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . O . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . O O . . O O . . |
$$ | . . X , X . . . . , X X . . . , X . . |
$$ | . . . . . . . . . . . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$ Position at move 28
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . O . . . . . . O X . . . |
$$ | . . . O . . . . . X . O . . . , X . . |
$$ | . . . . . . O . X . . . . . . X . . . |
$$ | . . O . . . . . . . . O . . . . . . . |
$$ | . . . . . . . . X . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . O . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . O O . . O O . . |
$$ | . . X , X . . . . , X X . . . , X . . |
$$ | . . . . . . . . . . . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Black:
- top right, a safe corner plus an extension, which threatens to undercut an enemy group
- lower right, a stable corner plus 4th line development
- lower left, a corner enclosure, which together with the lower right may form a moyo
- top, stones which are out in the centre and cutting off enemy stones
White:
- top right, an abandoned stone plus floating stones behind enemy lines
- lower right, central influence; the 4th line stone is influential but unstable
- lower left, two stones under development (the only truly efficient stones White has)
- top left, 4 stones developing a sphere of influence, but the corner can still be invaded and this will make the influence overlapping
This difference in efficiency is due to a number of unfavorable exchanges:
$$ Position at move 28
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . 8 . . . . . . O 7 . . . |
$$ | . . . O . . . . . X . O . . . , X . . |
$$ | . . . . . . O . X . . . . . . X . . . |
$$ | . . O . . . . . . . . O . . . . . . . |
$$ | . . . . . . . . X . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 9 . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . O . . . . . . . . . . . 0 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 2 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . 6 4 . . O O . . |
$$ | . . X , 1 . . . . , 5 3 . . . , X . . |
$$ | . . . . . . . . . . . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$ Position at move 28
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . 8 . . . . . . O 7 . . . |
$$ | . . . O . . . . . X . O . . . , X . . |
$$ | . . . . . . O . X . . . . . . X . . . |
$$ | . . O . . . . . . . . O . . . . . . . |
$$ | . . . . . . . . X . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 9 . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . O . . . . . . . . . . . 0 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 2 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . 6 4 . . O O . . |
$$ | . . X , 1 . . . . , 5 3 . . . , X . . |
$$ | . . . . . . . . . . . . . X . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
As Bill pointed out, the exchange of

-

is not good for White
Giving Black 4th line territory in exchange of 5th line influence is usually not good (3-4 and 5-6)
At the top, the not so ideal extension of

was done in exchange for strong corner territory at

And although not a direct exchange, the opposition of

and

is again in Black's favor. :w0: as an extension is way too close to its 4 stone wall.