Life In 19x19

Is the group on the left dead, alive, or seki?

This position is seki :

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[go]$$B Simplified situation
$$ | . . . . . .
$$ | O O O O .
$$ | X X X O .
$$ | X . X O . .
$$ | . O X O . .
$$ | O O X O . .
$$ | . . X O . .
$$ | X X X O . .
$$ | O O O O . .
$$ | . . . . . .[/go]

- Black can't live with points, because if black try to capture the white stones, it will be captured first

- white can't capture, because if white try to capture, it will give black a living shape inside. The important thing : Black must not play inside until the last moment :

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[go]$$B Black capture at a
$$ | . . . . . .
$$ | O O O O .
$$ | X X X O .
$$ | X W X O . .
$$ | W O X O . .
$$ | O O X O . .
$$ | a W X O . .
$$ | X X X O . .
$$ | O O O O . .
$$ | . . . . . .[/go]

Click Here To Show Diagram Code

[go]$$B Black capture at a
$$ | . . . . . .
$$ | O O O O .
$$ | X X X O .
$$ | X W X O . .
$$ | W O X O . .
$$ | O O X O . .
$$ | W a X O . .
$$ | X X X O . .
$$ | O O O O . .
$$ | . . . . . .[/go]

Click Here To Show Diagram Code

[go]$$B Black capture at a
$$ | . . . . . .
$$ | O O O O .
$$ | X X X O .
$$ | X W X O . .
$$ | a O X O . .
$$ | O O X O . .
$$ | W W X O . .
$$ | X X X O . .
$$ | O O O O . .
$$ | . . . . . .[/go]

Click Here To Show Diagram Code

[go]$$B Black capture at a
$$ | . . . . . .
$$ | O O O O .
$$ | X X X O .
$$ | X a X O . .
$$ | W O X O . .
$$ | O O X O . .
$$ | W W X O . .
$$ | X X X O . .
$$ | O O O O . .
$$ | . . . . . .[/go]

Awesome, thanks!

BTW, seki is a kind of life. In fact, mutual life is another term for seki.

And this is a situation where black can "die in gote". Black is alive (without points), but if black make the mistake of adding another move inside, his group is now dead and white can play elsewhere

Edit : wait, depending where black add his stone, white may need to answer to kill Or let black spend another move to save his group (still a seki)