How would yoou name this group?

[willemien]

While studying I stumbled on this group

$$B strange group
$$ ----------------
$$ | a X X O X . .
$$ | b O . O X . .
$$ | O O O O X . .
$$ | X X X X X . .
$$ | . . . . . . .

Click Here To Show Diagram Code

[go]$$B strange group
$$ ----------------
$$ | a X X O X . .
$$ | b O . O X . .
$$ | O O O O X . .
$$ | X X X X X . .
$$ | . . . . . . .[/go]

How would you call it?

a Ten Thousand Year Ko without a Ko?

Either player can start a [ko] (White at a, Black at b) but neither player would want to give their opponent the first ko capture.
so it is some kind of [Ten Thousand Year Ko|TenThousandYearKo]

Or is it as a Loss Making double ko threat?

or just an incomplete seki (Black can play ''a'' to make it a seki.

[robinz]

Doesn't a black play at a make a bent four in the corner (which is dead, unless white has unremoveable ko threats)? Thus I would say black to play can kill, and white to play must play at a to start the ko, even though black takes it first.

[HermanHiddema]

Doesn't a black play at a make a bent four in the corner (which is dead, unless white has unremoveable ko threats)? Thus I would say black to play can kill, and white to play must play at a to start the ko, even though black takes it first.

Correct.