this is a 1-pointer.(actually, you can miss by even less)
(
;
FF[4]
GM[1]
SZ[19]
AP[Jago:Version 4.31]
AB[bb][cc][dc][ec][fc][eb][gb][ga]
AW[ha][hb][hc][gc][fd][ed][dd][cd][bd][bc]
C[warning: this is an endgame problem. the black stones are completely safe.]
GN[temp]
(
;
W[da]
(
;
B[ca]
;
W[ab]
;
B[ba]
LB[ea:a][db:b]
C[RIGHT now black needs to play two more moves inside at a and b.]
)
(
;
B[db]
C[wrong defence.]
;
W[ba]
;
B[cb]
;
W[ab]
;
B[ea]
C[RIGHT black still lives, but looses points]
)
)
(
;
W[ab]
;
B[ba]
;
W[da]
;
B[db]
LB[ea:a]
C[black only needs to play one more move inside at a.]
)
(
;
W[ba]
;
B[cb]
;
W[ab]
;
B[ca]
C[5 points for black. the same as the correct solution. but black can exchange a for b, making this 2/3 of a point worse for white. (a ko with no further implications is worth 1/3 of a point, because one side needs 1 move to connect, and the other side needs 2 moves to capture and connect, making it 1 point for 3 moves)]
LB[aa:a][ac:b]
)
)