(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PW[White]PB[Black]C[Starting around move 9 for black, we look at some modern variations, several of which may be new to readers. The reason is the "classic" joseki(the first reference I can find to this is from 1987) has now been deemed slightly good for white in Korean professional study groups, and so professionals have moved on to alternatives.

I saw some of the ideas here in a game review on Go Game Guru web site, and also saw Gansheng Shi 1P looking at some related variations in another game review on the baduk movies web site.]
;B[pp]
;W[dp]
;B[qd]
;W[dd]
;B[nc]
;W[qj]
;B[qh]
;W[qn]LB[np:A][nq:B]TR[qh][qj][qn][pp]C[A is the normal move in this position with the triangled stones in place and most of the analysis here follows from A, but for a while B was popular See the variation for what was tried and why it fell out of favor.]
(;B[np]
;W[fc]LB[ql:A][rl:B][on:D][qo:C]C[For several years(the earliest example I saw of the pattern was from 1987), the result after the invasion at A and then an white answer with an attachment underneath at B(see variation) was the standard joseki here in professional play. Of course white D in response to A is also a classic move, but we won't look at in this discussion. However A followed by B has now been judged good for white, and so black tries starting with C.]
(;B[qo]LB[pn:A][rn:B]C[Again readers may be more familiar with the white answer at A, but in the game B was played, and this leads to a new candidate joseki pattern.

For a while A fell out of favor, but Gansheng points out couple variations that now are acceptable for white, and so A is being played again.

The move at B will remain in professional play until study groups decide the variation is favorable for white or black. Of course those of us outside the oriental professional circles may never realize why we stop seeing the pattern show up in professional play.  Its even possible this has already happened!]
(;W[pn]
;B[ql]LB[pl:A][rl:B][op:C]C[The result after A hae been judged good for black (see that variation), so  white typically started with B(see variations).  However Gansheng points out newer variations following from A where white makes use of the wedge at C that are still being played.]
(;W[pl]
;B[rl]LB[pk:A][op:B]C[The result after A is better for black (see variation).  However Gansheng points out the move at B has been discovered, and gives a couple variations that have been played recently.]
(;W[pk]
;B[rn]
;W[mm]C[This is good for black, as black's corner territory is too large])
(;W[op]
;B[oo]
;W[po]
;B[oq]
;W[qp]
(;B[ro]
;W[rn]
;B[qq]
;W[rp]
;B[rq]
;W[so]
;B[pk]
;W[ol]
;B[pj]
;W[on]C[This variation is being played often now.])
(;B[qq]
;W[ro]
;B[rp]
;W[pk]
;B[om]
;W[pm]C[Also popular recently.])))
(;W[rl]
;B[rm]
;W[rn]
;B[rk]
;W[pl]
;B[rj]
;W[mm]
;B[kq]C[This is playable.  But the consensus is that it is a bit better for black.]))
(;W[rn]LB[qk:C][ql:A][rl:B]C[The idea with this move is if black tries to invade at A, B makes a nice connection.  So the attachment at C (first played by Lee Chang Ho) becomes the key to attacking white's position now.]
;B[qk]LB[rk:C][pl:E][rl:D][ro:B][qq:A]C[The timing here is subtle.  White would like to be able to exchange A for B before continuing with C followed by black D.  But if A/B have been exchanged black should switch to E instead of D.  E is not normally a good shape, but in this case it works well for black.  See the variation for white A now, instead of C.]
(;W[rk]LB[rl:A]
;B[rl]LB[rj:C][ro:B][qq:A]C[White would like to be able to exchange A for B, before continuing to answer this black move.  If black answers A at B the result is good good for white.  So black continues at C, see the variations from A.]
;W[qq]LB[rj:B][ro:A]C[The natural move at A won't give a good result. So black tenuki's and plays B (see the continuation).]
(;B[rj]
;W[qp]
;B[pj])
(;B[ro]C[A mistake.]
;W[ql]
;B[pk]
;W[rj]
;B[qm]
;W[pl]
;B[pm]
;W[ol]
;B[rm]
;W[om]
;B[pn]
;W[oi]LB[ro:B][qq:A][nr:D][pr:C]C[The exchange of A for B turns out to be very good for white.  If white played A now black would play C to capture it.  And of course A will help greatly now when white plays a move like D to reduce the black territory.  The final result here is a sucess for white.]))
(;W[qq]
;B[ro]
;W[rk]
;B[pl]
;W[rl]
;B[pn]TR[ro][qq]SQ[qj][rk][rl][qn][rn]C[Here the triangled exchange is a negative for white, as it weakens the marked group, and also closes the door to a later white reduction at s4 to the black corner.  It is interesting to contrast this with the variation given later where the same triangled exchange is good for white.])))
(;B[ql]
;W[rl]
;B[rm]
;W[qm]
;B[rk]
;W[rn]
;B[qk]
;W[qq]
;B[qp]
;W[rp]
;B[pq]
;W[rr]
;B[qr]
;W[rq]
;B[jq]))
(;B[nq]
;W[fc]
;B[ql]
;W[rl]
;B[rm]
;W[qm]
;B[rk]
;W[rn]LB[qk:A][rp:B]TR[nq]C[Because triangle is low B is very nice for black now, and so  the varation with black playing B now was popular for a while.  However white can then take A, and is still able to get a result which has been deemed good for him by professional study groups (see the continuation).]
;B[rp]
;W[qk]
;B[sl]
;W[pl]
;B[rj]
;W[rl]C[This variation appeared for a little while, but then was discarded.  White will win the ko as "there are no ko threats in the opening" and it gives white too thick a position.]))
