It was an accident on the board.
White was ahead but I don't think that this is easy to see. However, after making some timesuji like move Shibano, who is white, seemed to have a blind spot and played something that didn't work out. So in the end it was Yamashita that won.
You can have a Go at finding the right move.
- Click Here To Show Diagram Code
[go]$$W White to play.
$$ +--------------------------------------+
$$ | . . . . O X X . . . . . . . . . . . .|
$$ | . . . . O O X . . . . X . . O O O O .|
$$ | . . . . X O . X . 1 X . O O X O . . O|
$$ | . . . O O O X X X 2 O . O X X X O O .|
$$ | . O O . . X O X O O . X X X . . X X .|
$$ | . O X X . . O X X O . . O O O X X . .|
$$ | . . . . . O X X X O . O . . X . . . .|
$$ | . . . . . X O O O O O X X . . . . . .|
$$ | . . . X X X O . O X X . . X . . . . .|
$$ | . . X X O O . O O , O X . X . , . X .|
$$ | . X O X X O O O X O . X X X X O X X O|
$$ | . O O X O X X X X X X X . X O X X O .|
$$ | . . O X O O X . . O O O O O O . O . O|
$$ | . . O . O X X . O O X X O . O . O O .|
$$ | . . . . O X . X . . . . . O . X . . .|
$$ | . O O O X O O . O O X X . . . X . O .|
$$ | . O X X X X O O O . O X . X . X O . .|
$$ | O X . . X . X O X O O O X . . . X X .|
$$ | . X . . . . 4 X X 3 . X . . . . . . .|
$$ +--------------------------------------+[/go]
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