(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[0.00]
PW[백 Cho Hye Yeon 9p]PB[BadukMovies]C[Today's topic: nose tesuji.]
(;AW[ob][pb][mc][nc][pc][qc][dp][pp]AB[nb][oc][dd][nd][od][pd][qd][qj]
;B[lc]C[This is a 'nose tesuji'.

]
(;W[md]
;B[mb]
;W[ld]
;B[kc]C[Black succeeds. 
])
(;W[mb]
;B[md]
(;W[lb]
;B[kc]C[Black is satisfied with it.
])
(;W[ld]
;B[jc]
;W[le]
;B[lb]
;W[na]
;B[je]C[Black succeeds! 
])))
(;AW[db][dc][fc][nc][ed][nd][de][ne][lf][mf]AB[cc][ic][lc][cd][dd][od][pd][ce][le][cf][qg]C[This is the problem - white to play (on the right side)]
;W[qd]C[This is the nose tesuji.
]
(;B[qe]
;W[qc]
;B[pb]C[If black plays here...
]
;W[pc]
;B[oc]
;W[ob]
;B[nb]
;W[pe]
;B[oa]
;W[oe]
;B[ob]
;W[qf]C[White succeeds!
])
(;B[qc]
;W[qe]C[White is happy. And then...
]
(;B[pf]
;W[rc]
;B[pb]
;W[qb]
;B[pc]
;W[rb]C[White succeeds!
])
(;B[pe]
;W[rc]
;B[pb]
;W[qb]
;B[pc]
(;W[rb]
;B[qf]
;W[re])
(;W[rg]C[White is fine.
]))))
(;B[pd]C[This was the official match between Lee Changho 9p(White) and Cho Hunhyun 9p, played on 21st December in 1997. This is the final]
;W[dp]
;B[pp]
;W[dd]C[This was the official match between Lee Changho 9p(Black) and Cho Hunhyun 9p, played on 21st December in 1997.
]
;B[fq]
;W[cn]
;B[jp]
;W[qn]
;B[ql]
;W[qq]
;B[pq]
;W[qp]
;B[po]
;W[rn]
;B[om]
;W[hq]
;B[hp]
;W[iq]
;B[ip]
;W[jq]
;B[kq]
;W[kr]
;B[gq]
;W[lq]
;B[kp]
;W[mr]
;B[hr]
;W[is]
;B[cq]
;W[dq]
;B[dr]
;W[cp]
;B[br]
;W[bq]
;B[cr]
;W[ck]
;B[fc]
;W[hc]
;B[cc]
;W[dc]
;B[cd]
;W[de]
;B[db]
;W[eb]
;B[cb]
;W[ec]
;B[cf]
;W[kc]
;B[qf]
;W[mo]
;B[ok]
;W[nc]
;B[kd]
;W[lc]
;B[oc]
;W[nd]
;B[id]
;W[ic]
;B[of]
;W[nf]
;B[ng]
;W[oe]
;B[pf]
;W[pe]
;B[qe]
;W[qc]
;B[qd]
;W[ob]
;B[mf]
;W[rl]
;B[rk]
;W[qm]
;B[pl]
;W[sk]
;B[sj]
;W[sl]
;B[rj]
;W[mm]C[This is the problem.
Cho Hun-hyun 9p pointed out that...
]
(;B[sn]C[Black should attach here at this point, being a nose-tesuji.
]
(;W[rm]C[If white connects here,
]
;B[qr]
;W[rr]
;B[rq]
;W[rp]
;B[sr]
;W[rs]
;B[or]C[This marked stone becomes sente(seonsu in Korean).
]
;W[kn]C[When white plays tenuki..]
;B[sp]C[Black can make a ko in the corner])
(;W[so]C[If white responds to the nose attachment...
]
;B[ro]
;W[qo]
;B[sp]
;W[rm]
;B[qr]
;W[rr]
;B[rs]C[Much better than the actual game!
]
(;W[sr]
;B[or]
;W[kn]
;B[rp]C[It becomes a sente seki(Seonsu Bik in Korean). 
])
(;W[pr]
;B[ps]C[This would be ko again]
;W[or]
;B[rq])))
(;B[qr]C[This is the sequence of the actual game...(move 79)
]
;W[rr]
;B[rs]
;W[sr]
;B[or]
;W[kn]
;B[lk]
;W[kf]C[White is fine! 
]
;B[sn]
;W[rm]
;B[sp]
;W[rp]C[White is alive now]))
(;AW[cc][ic][jc][kc][lc][cd][hd][md][de][ef][mf][eh][gh][hh][kh][lh]AB[cb][eb][dc][fc][hc][oc][id][jd][kd][pd][qe][gg][kg]C[Black to play and connect all his stones.]
(;B[he]C[Wrong.]
;W[gd]
;B[ge]
;W[fd]C[Black is in crisis!
])
(;B[gd]
;W[he]
;B[hf]C[This is a nose tesuji!
]
;W[ge]
;B[fe]
;W[ie]
;B[if]
;W[je]
;B[ke]
;W[jf]
;B[jg]C[This is like an empty ladder!
]))
(;AW[mm][pm][pn][lo][mo][no][po][qo][op][oq]AB[nn][on][oo][kp][lp][mp][np][pp][qp][rp]C[A tsumego, black to move: dead or alive?]
(;B[pq]
;W[or]C[Black's failure! 
]
;B[pr]
;W[mr]C[Black is dead!
])
(;B[or]C[This is a nose tesuji!
]
;W[pq]
;B[pr]
;W[qq]
;B[rq]
;W[qr]
;B[rr]
;W[nq]
;B[nr]
;W[mq]
;B[mr]
;W[lq]
;B[kq]
;W[lr]
;B[kr]C[Black wins the capturing race by one move!
]))
(;AW[qb][fc][kc][oc][pc][ld][le][me]AB[mc][qc][rc][dd][md][od][pd][qe][df]C[The top right is the problem. White to play.]
;W[mb]C[This is a nose tesuji.
]
(;B[nb]
;W[nc]
;B[nd]
;W[ob]
;B[lb]
;W[na]C[White succeeds!
])
(;B[lb]
;W[nb]
;B[lc]
;W[nd]C[Black's failure!
]
;B[kb]
;W[jc]))
(;AW[cn][cp][dp][ep][gp][cq][gq]AB[fo][go][ho][io][dq][eq][iq]C[The problem, black to play (similar to the previous one).]
;B[gr]C[This is a nose tesuji.
]
(;W[hr]
;B[fp]
;W[fq]
;B[fr]C[White is ruined!
])
(;W[fr]
;B[fq]
;W[fp]
;B[er]
;W[hr]
;B[fs]C[Black succeeds!
]))
(;B[dq]
;W[do]
;B[fp]
;W[cq]
;B[cr]
;W[cp]
;B[br]
;W[gp]
;B[fo]
;W[fq]
;B[eq]
;W[gq]
;B[go]
;W[ho]
;B[hn]
;W[io]
;B[cm]
;W[dm]
;B[cl]
;W[gn]
;B[fn]
;W[gm]
;B[hp]
;W[ip]
;B[hm]
;W[fm]
;B[hl]
;W[dr]
;B[fl]
;W[em]
;B[gl]
;W[kp]
;B[dk]
;W[ko]LB[ep:B][er:A]C[The problem. Black to play!
]
;B[gr]C[Not to mention, this is a great nose tesuji! 
]
(;W[fr]
;B[er]
;W[hr]
;B[ep]C[Black smiles!
])
(;W[hq]
;B[ep]C[The effect of the nose tesuji!
]
;W[er]
;B[fr]
;W[hr]
;B[ds]))
(;AW[dm][em][fm][gm][bn][cn][hn][bo][ho][bp][hp][bq][cq][fq][gq][hq][gr]AB[dn][en][fn][co][eo][fo][go][cp][dp][ep][fp][gp][dq][iq][dr][fr][fs]C[White to play and kill.]
;W[ds]C[This is a nose-tesuji.
]
;B[cr]
;W[er]
;B[eq]
;W[gs]C[Easy, right?
]))
