Elizabeth: After wA17, bA16, wA12, black has a tesuji at bA18.
After the tesuji if wB17 then bB19 starts a ko.
If, instead, white takes with wA19, bB17 starts another ko which is dangerous for white.
Ivan Detkov: I agree. Although the risk of ko is asymmetric, it could be a viable strategy. I corrected the sequence.
StephaneLamy: I don't see why A17 (or A3 in the sgf file) is inferior to the correct solution A18.
In fact it seems with A17 one can get one more point (in gote)
I agree. Although the risk of ko is asymmetric, it could be a viable strategy. I corrected the sequence.