TherapieGo: I've put the sequences in an SGF file to explain my 2 messages ;)
caranthir: Thank you. I updated variations. You were right about T18, and therefore everything starting with R17 is probably refuted. About P19O19R18, it was right in general, though there were a couple of endings in the SGF which I think I refuted. -------- This prompts me to think how the ranks of these problems really have to be taken with a grain of salt. As I'm writing, this is a "2 dan problem". That's a joke really. It would represent closer to 2 dan *professional* strength to thoroughly understand these kind of positions on the spot or even with a bit of thinking. Otherwise we (I mean, especially @TherapieGo) wouldn't be finding mistakes or oversights in already established sequences still, over and over.
caranthir: It seems to possibly lead to some kind of ko (a difficult for the opponent, but ko nonetheless), as far as I can tell. Can you show a definite kill starting with E19?
Thank you. I updated variations. You were right about T18, and therefore everything starting with R17 is probably refuted. About P19 O19 R18, it was right in general, though there were a couple of endings in the SGF which I think I refuted. -------- This prompts me to think how the ranks of these problems really have to be taken with a grain of salt. As I'm writing, this is a "2 dan problem". That's a joke really. It would represent closer to 2 dan *professional* strength to thoroughly understand these kind of positions on the spot or even with a bit of thinking. Otherwise we (I mean, especially @TherapieGo) wouldn't be finding mistakes or oversights in already established sequences still, over and over.