A false seki is a position that looks like a seki but is not, because one player’s stones are actually dead. A false seki may be a temporary seki that has collapsed, or it may be a position that arose in killing the dead stones.
This example comes from this Chinese site. After , - form a false seki.
Yes, a dead bent four in the corner is a false seki.
( on the 1-1 point would have lived.)
This false seki actually happened in the upper left corner of a very large board of size, hold your breath, 38×38 ( SGF with 1001 moves :-). Black was erroneously not declared dead, but it didn’t matter anyway. — RP
Bass: To me these three final diagrams do not seem like examples of false seki. They are plainly dead (we’ll talk about the bent four later ;-) ) and I do not think there is any need for a term that means “dead, but somebody once misread it as seki”. However, the first diagram displays a “proper” false seki, where there are groups that are locally in a seki, which will however collapse because some of the surrounding stones will get killed. In my opinion, this is a much more useful meaning for the term.
Googleplex?: I agree - in the last two examples it is possible for the target colour to make life.
W would play circle instead of 2 in the last example and in the previous one, black is able to make two columns of two, each as good as an eye.
MrTenuki: I think the reason that the last example is listed here is that the situation is similar to “real” sekis in one way: if either Black or White plays a stone locally, the other player may capture. What makes the seki false in this case, then, is the fact that, for White, capturing after Black plays a stone locally still does NOT make life (while Black may save the four stones if White plays locally first).
Zar?: We mention that a group is dead with a false eye, don’t we? I could argue that the group is simply dead and that is simply not an eye. Consider it an educational term. The first example’s just dead as well in my opinion.
Patrick Traill: Since a Chinese translation is given, this page should presumably reflect the usage of that expression in China. I am inclined to agree with Zar? that this term is no less useful than “false eye”.