Counting a surrounded non-alive carpenter's square
During the game

$$
$$ -------------
$$ | a b O X O .
$$ | X O O X O .
$$ | . X , X O .
$$ | X X X X O .
$$ | O O O O O .
$$ | . . . . . .


The corner is not settled yet, as both players can choose to:


either start a ten thousand year ko, white by playing at a and black by playing at b
or settle for a seki, if black plays at a or white plays at b.


At scoring time

If no move has been added in the corner, I would expect this to be considered a seki under Japanese rules (see example 12).

Under Chinese rules, both players would have to agree on the seki, or keep playing (in which case a or b will eventually be played).