Mickeymmm: I don't truly understand why kick is not good here ? San-San is doing something ? how ?
caranthir: Rationale behind D18: 1) The corner _is_ more solid with D18 compared to E17. 2) White already has a stone at K16, which makes answering to the kosumi-tsuke (kick) more valuable. --- That said, if sente is important, then according to Katago for instance E17 can sometimes be better than D18. For instance, if there are any unoccupied corners, then playing E17, and after opponent F16, grabbing a corner - or better still, grabbing a corner right away. But, say, all other corners were occupied by a stone at 3-3 of either colour. Then D18 is better than E17 (actually, according to Katago, D18 is globally best). --- I'd still argue against including E17 here, lest it's a big mess in reviewing and modifying a whole bunch of other Kano problems. The point of the problem is to learn to think about the best *local* move in the corner. It's not necessarily the best kind of exercise in the Tsumegohero format, as the verbosity of my explanation probably shows.
Rationale behind D18: 1) The corner _is_ more solid with D18 compared to E17. 2) White already has a stone at K16, which makes answering to the kosumi-tsuke (kick) more valuable. --- That said, if sente is important, then according to Katago for instance E17 can sometimes be better than D18. For instance, if there are any unoccupied corners, then playing E17, and after opponent F16, grabbing a corner - or better still, grabbing a corner right away. But, say, all other corners were occupied by a stone at 3-3 of either colour. Then D18 is better than E17 (actually, according to Katago, D18 is globally best). --- I'd still argue against including E17 here, lest it's a big mess in reviewing and modifying a whole bunch of other Kano problems. The point of the problem is to learn to think about the best *local* move in the corner. It's not necessarily the best kind of exercise in the Tsumegohero format, as the verbosity of my explanation probably shows.