(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PW[White]PB[Black]
(;C[Subject of this lesson: HANE

]
(;W[od]C[With a high move on a 5-4 point, sometimes black will invade on 3-3.]
;B[qc]
;W[qe]
;B[oc]
;W[nc]
;B[pd]
;W[pe]C[We can then arrive at this position.]
(;B[nb]C[This is a great hane.]
(;W[nd]
;B[mb]C[Black has a good shape.]
;W[rc]
;B[rb]
;W[pb]C[This peep seems like a painful point, but black can manage.]
;B[pc]
;W[rd]
;B[sb]C[Black can extend.])
(;W[mc]C[If white extends,]
;B[mb]
;W[lc]
;B[lb]
;W[kc]C[Black pushes two times and then..]
;B[oe]C[There is a cuttingpoint!]
;W[nd]
;B[of]C[Black can reduce white's influence.])
(;W[ob]
;B[pc]
;W[mb]
;B[nd]C[Double atari.]))
(;B[nd]C[We think about this move first.. but..]
;W[oe]
(;B[nb]
;W[mc]
;B[mb]
;W[lc]
;B[lb]
;W[kc]LB[nd:A][oe:B]C[When we compare this to one of the previous variations, we can see that the exchange of black A for white B is good for white. This cut is wrong since white becomes stronger. ]
;AE[nd][oe]C[If we compare it to this cut...]
;B[oe]
;W[nd]
;B[of]C[We can see this is the better cut for black.])
(;B[mc]C[Trying to capture white depends on a ladder.
When the ladder is good for black, this variation is worth thinking about.]
;W[nb]
;B[ob]
;W[md]
;B[ne]
;W[mb]
;B[lc]
;W[ld]
;B[lb]
;W[nf]C[The ladder.])))
(;W[qe]C[The same position can arise from a 3-5 point, when black invades on 3-3.]
;B[qc]
;W[od]
;B[oc]
;W[nc]
;B[pd]
;W[pe])
(;AB[cp]
;W[fp]C[Approaching the 3-4 point in this high way is a joseki move.]
;B[hq]
;W[dp]C[To settle white can attach.]
;B[do]
;W[cq]
(;B[bq]C[Another great hane which is part of a joseki.]
;W[dq]
;B[bo]
;W[eo]
;B[dn]
;W[br]C[This exchange is important.]
;B[ar]
;W[en]
(;B[dm]LB[ho:A][ip:B][jp:C]C[After that you can think about A to C. These are Josekis.])
(;B[em]C[If black hane here,]
;W[dm]C[the cutting works..]
;B[dl]
;W[cm]
;B[cl]
;W[bm]
;B[bl]
;W[co]
;B[cn]
;W[bn]
;B[co]
;W[ao]
;B[bp]LB[ar:B][br:A]C[You can see why the exchange A and B is good.]
;W[aq]))
(;B[co]C[If black just connects,]
;W[dq]C[white also connects.]
;B[bq]
;W[br]C[now white can block. ]
;B[eo]
;W[gq]
;B[hp]
;W[fo]C[After that white can split the groups and hope for an attack.])
(;B[ep]
;W[dq]
;B[eq]
;W[co]
;B[eo]
;W[cn]TR[eq][hq]C[The corner is too big and black's marked stones are overconcentrated.])))
(;AW[jc][qc][pd][je][mf][pf][qi][ck][bn][cn][in][jn][kn][cp][cq]AB[cc][hc][pc][ed][nd][dk][bl][cl][em][do][io][jo][dp][dq][jq]LB[pc:1][qc:2]TR[bn][cn][cp][cq]C[Black plays 1 and white blocks with 2. What should black play?]
(;B[oc]C[This is normal.]
(;W[qb]C[But white descends and this is painful.]
;B[lc]
;W[kb]C[Black has little eyeshape.])
(;W[qd]C[Not a good move, passive.]
;B[qb]
;W[rb]
;B[lc]C[Black can more easily make life.]))
(;B[qb]C[In this case this hane helps black to make eyeshape.]
(;W[oc]
;B[pb]
(;W[od]
;B[qd]
;W[rc]
;B[rd]
;W[rb]
;B[ra]C[Black can live easily.
])
(;W[qd]C[If white connects here...black should be careful.]
(;B[od]C[This is dangerous.]
;W[nb]
;B[mb]
;W[mc]
;B[nc]
;W[lb]
;B[ob]
;W[ma]
;B[rc]
;W[rd]C[Black can not live easily. ]
(;B[sc]
;W[ra]
;B[rb]
;W[sa]
;B[oa]
;W[qa]C[Bent four in the corner, black is dead.])
(;B[ra]C[A ko.]
;W[sc]
;B[sb]
;W[rb]C[White is happy with this ko.]))
(;B[nc]C[This is correct.]
;W[od]
;B[ob]
;W[mb]
;B[nb]
(;W[rb]C[Seems dangerous, but black can live or escape with some magic.]
;B[kd]C[Here peep is nice. ]
(;W[kc]
;B[ld]
;W[mc]
;B[md]
;W[jd]
;B[lf]C[Black can escape.])
(;W[lc]
;B[me]
;W[lf]
;B[ke]
;W[kf]
;B[jd]C[There are too many cutting points.]
;W[id]
;B[ic]))
(;W[lc]C[This seems more reasonable, but black lives in the corner.]
;B[rc]
;W[rd]
;B[rb]C[Black lives]))))
(;W[qd]
;B[oc]
;W[rb]
;B[lc]C[Black has enough space to live. ]))
(;W[]C[In the lower left, there is also a secret hane. Can you spot it?]
(;B[co]C[Pushing here first is crucial if you wish to play the secret hane. (for ko)]
;W[bo]
;B[cr]
;W[br]
;B[bs]C[There is a hane in this shape. Ko!]
;W[dr]
;B[ds]C[Black can make ko, if black has enough ko threats.]
;W[er]
;B[bq]C[The corner is at stake.])
(;B[cr]C[Playing here immediately is a mistake if you want to play the ko.]
;W[br]
(;B[dr]C[This is normal endgame, white defends the corner.]
;W[bs])
(;B[bs]LB[co:A]C[Without black A there is a difference!]
;W[dr]
;B[ds]
;W[er]
;B[bq]
;W[ar]C[In this case white can extend. ]
(;B[co]
;W[bp]
;B[bo]
;W[aq]C[White is happy with this.])
(;B[aq]
;W[bp]
;B[as]
;W[fq]C[There is still a ko, since white has to fill the corner to capture black. But this is a many step ko for black. Therefore it is much better for white.]))))))
