(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2] RU[Japanese]SZ[19]KM[7.00] C[Why are many joseki symmetric? I used to think this was because tighter attacks require more solid responses and this is in part true. Often it is just coincidence too.] (;B[qc] (;W[pe] ;B[od]C[The key point for sure. White's threat of Q17 is pretty much cut off (white can only start from R16 now). White's push of Q16 becomes completely crude. White can't easily develop the stone.] (;W[qd] ;B[pd] ;W[qe] ;B[rc] ;W[qi] ;B[ld]C[a joseki shape that is good for B. If M16 was at O16, then it would be even and a normal joseki.]) (;W[mc]C[unlikely to do much since B's moves at P15 and Q16 damage Q15 greatly, so B is actually very thick.] ;B[oe])) (;W[qe]C[this blocks off the corner from the side with one move but risks being counter-attacked] (;B[oc]C[good move though P16 normally better but why? Sometimes this is preferred over P16 because there is better control of the corner and S17 may be met by S16 sometimes. A solid move is good when your opponent comes near because even though you have less, you are more easily able to kill the approach stone with a pincer move.] ;W[pd]C[the problem in this shape is this is sente.]) (;B[od] ;W[pg])) (;W[pf] (;B[nd]C[normal response since Q14 is one further away, black doesn't need to defend against Q17. Locally, this ensures W's attack at P17 is cut off from Q14 (especially as B can attach at Q15) As attacks at P16 are met with black connecting underneath (since B shorting W's liberties means that B gets the extra forcing move required to connected a two space extension), the shape is secure for now. If white does endgame from the outside with Q16 or R16, this is big, but O16 remains perfectly placed (better than P16 anyway). As white doesn't have a base, black is more interested in attacking so 4th line is good. In addition, white's main potential with the high stone is to continue in the centre so preventing that by raising the head on the 4th line is good.] (;W[cq] ;B[dd] ;W[dn] ;B[ep]C[this is a key shape point to aim at C4] ;W[dp]C[strongest response but the cutting point is still there] (;B[eo]) (;B[eq]C[either way, B's shape is good])) (;W[qe]C[this still has no real threat other than S17 and P17] ;B[ld])) (;B[od]C[This is completely fine but white has several annoying options locally] (;W[qd]C[what to do? P16 will always be overconcentrated like this.]) (;W[mc]C[B is thinner after white P16 but white's seal at O15 is also more secure]))) (;W[qf] (;B[nc]C[normal response though it depends the next move at Q15 is still quite big] ;W[od] ;B[oc] ;W[qd] ;B[dp] ;W[pc] ;B[pb] ;W[pd] ;B[rb] ;W[rc] ;B[qb]TR[oc][od]C[This is a standard joseki except the marked exchange has been added which looks fairly even but I slightly prefer W since P16 is certainly useful for the weak W group and P17 gains only 1 point and a defence of P18. But W couldn't really play P18 before (to threaten it via Q18 is difficult as W needs to play S16 then T18 then S19, via P17 is difficult as that is empty triangle and the corner can live with S16, via O17, N17, O18 would be normal but after this exchange O17 is still a bit low on liberties, so seems good for W).]) (;B[oc]C[Playing a one space would be too inefficient as W is far away enough that it is difficult to attack W] (;W[pd]C[This is still a problem] ;B[qd] ;W[od] ;B[pc]C[W's shape is not too bad for sabaki (if pincered already)]) (;W[mc]C[W can pressure B more easily as R14 can't easily be leaned on.])) (;B[nd]C[if you play like this which is still possible, the follow up at Q15 is less efficient] (;W[lc] ;B[pe] ;W[qe] ;B[qd] ;W[pf] ;B[oe] ;W[nb]) (;W[qi]))) (;W[qg]C[further away is often met with tenuki] (;B[qe]) (;B[ld] (;W[qe] ;B[od]C[this is great for B]) (;W[dp] ;B[qe]C[this is also not bad for B])))) (;B[pd] (;W[qf] ;B[nc]) (;W[pf] ;B[nd]C[high is normal to protect the P16 point from Q14 though low is fine too. When your opponent comes so close, the main follow ups are local fighting. Even if they can't fight now, with just some extra support, it will happen later. So it is better to use just one move to remove that problem.]) (;W[qg]C[further away moves aren't so tight and black has many good responses including tenuki. It depends on the situation. Since B can't lean on W so easily, it can make a double approach by W more powerful sometimes for sealing B in.] (;B[mc]C[this is common though O17 is fine too. This makes B's follow up at R15 more efficient and W also can't easily invade the corner. The point is that W is likely going to add more moves around S16 and B will be happy to respond as the next move will still be big with plently of unsettled space. So playing loosely to start of with means that even when you continue responding, your shape remains efficient.]) (;B[nc] ;W[rd] ;B[qc] (;W[qj]C[this is often more efficient and speedy shape for W than the usual joseki.]) (;W[rc] ;B[qi] ;W[pe]C[this too])))) (;B[qd] ;W[dp] (;B[od]C[3-4 shimaris tend to be better at double wing moyos than 4-4 stones which require more attention to the corner but that can give the opponent more ways to reduce.] (;W[qf]C[approaching this side is less interesting as B already has such good control over this area. W's threat of S16 is mostly defended against since P16 helps protect the cutting point at R17 by defending the cut at Q16 created (since B owes a move to help S17 anyway, the extra support for R16 is critical). W's follow up at P14 can be difficult to curl around but it isn't a great threat against B if B can just respond N16 to take more territory, while the W stones are still vulnerable.]) (;W[mc]C[This is also less popular post AI. It seems that W doesn't really have a good follow up in the corner since W isn't able to cut Q16. If W is only able to peep at Q17, making B so solid isn't great when N17 and Q17 are still not connected and B has potential on the right side. moves like P18 are big but slightly too slow.])) (;B[nd] (;W[lc]C[This is big now because the threat of cutting with Q16 is real] ;B[pp] (;W[pd]C[curious that the further away cut is more powerful. But that is because you lean on the strong stone to attack the weaker. If ] ;B[pc] ;W[oc] ;B[od] ;W[pe]C[you create problems for B in the corner with the R16 group. This gives you more forcing moves with the cutting stones. These cutting stones are cutting O16 off, so the fight is ok for W.] ;B[qc] ;W[nc]) (;W[od]C[this is bad shape because to follow up, you need to keep saving the cutting stone] ;B[oc] ;W[pc] ;B[pd] ;W[oe] ;B[nc]C[but then M17 is misplaced as this sequence gives W corner aji with R17 but then R16 is the weaker group and M17 isn't attacking that. B gets too strong with the O16 group by just responding to W.])) (;W[qf]C[the threat of cutting with P16 is real] ;B[pp] ;W[od] ;B[oe] ;W[qc]))))