Different versions of Rn different results

[a22063821]

Time and parameters are the same

Rn4.14 results

Top left corner white died

Rn4.20.4 results

Top left corner white is alive

Why is this situation?
Rn4.14 grasp the superiority
Rn4.20.4 give away the advantage

[crayzok]

I think Rn4.14 made a bad choice and 4.20 picked not bad choice(stable choice).

Rn4.14 missed fact that 6 black stones cannot live despite of A10 move.

Rn4.20 knew that and she felt that Ko at the left-top corner is quite burdensome...

Because black group at the left-top corner are still not alive too.

And she judged that black still hold a lead this game after black give away 5 black stones at the left side.

If I just connect 4 black stones at the left side by putting D9, that's super-Ko.

[a22063821]

C-point location will be better Rn

Rn 10 times choices, 6 times A, 3 times B, 1 times C
Rn selects C chances low

[crayzok]

yeah, choice of A is stable because it removes Ko but it gives away 4 black stones.

choice of B and C is risky because black group at the left top corner aren't still alive but combative and favorable choice.

B is better than C because of Ko threat(劫材) and B9 move of white.