(;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 is the wedge tesuji.
]
(;AW[oa][ob][qb][sb][qc][sc][qd][rd]AB[na][ra][nb][rb][nc][rc][nd][pd][pe][qe][re][se]C[Black to play.]
(;B[sd]C[Wrong.]
;W[qa]
;B[pb]
;W[sa]C[White is alive!
])
(;B[pb]C[Wedging move!
]
;W[pc]
;B[oc]
;W[pa]
;B[sd]C[White cannot live!
]))
(;AW[jb][ob][pb][qb][ic][kc][mc][md][od][qd][sd][me][se][nf][of][pf][qf][rf]AB[ka][la][ma][na][oa][pa][qa][ra][lb][mb][nb][rb][nc][rc][nd][rd][ne][re]C[Black to play.]
;B[pd]C[Wedge!
]
;W[pe]
;B[pc]C[Easy, right?
]
;W[oc]
;B[qc]
;W[oe]
;B[qe]C[black lives])
(;AW[na][nb][qb][nc][oc][nd][qd][ne][of][pf][qf][rf][rg]AB[oa][pa][ra][ob][rb][od][oe][pe][qe][re][sf]C[Black to play.]
(;B[pc]C[Wrong.]
;W[qc]
;B[pd]
;W[rd]
;B[pb]
;W[qa]C[Black is dead!
])
(;B[rc]C[Wrong.]
;W[qc]
;B[rd]
;W[se]
;B[pc]
;W[qa]C[black can not live]
;B[sd]
;W[sb])
(;B[qc]C[Wedge!
]
(;W[rc]
;B[pc]
;W[rd]
;B[pd]C[White is ruined!
])
(;W[pc]
;B[rc]
;W[rd]
;B[sd]
;W[pd]
;B[pb]C[This is 'ishino sita' (under the stones).
]
;W[qa]
;B[pb]C[Black is alive!
])))
(;AW[pa][ob][pb][qb][nc][rc][sc][pd][ne]AB[na][oa][qa][ra][mb][nb][rb][lc][ld][le][oe][pe][mf][nf][qf][rf][sf]C[Black to play. ]
(;B[qd]C[Not optimal.]
;W[od]
;B[qc]
;W[pc]C[Black has to...
]
;B[nd]
;W[md]
;B[me]
;W[sb]
;B[nd]C[make only a ko.
])
(;B[od]C[This move is even worse.
]
;W[qd]
;B[oc]
;W[pc]C[White is happy!
])
(;B[pc]C[Wedge!
]
(;W[qd]
;B[oc]
;W[qc]
;B[od]C[White screams !
])
(;W[oc]
;B[qd]
;W[qc]
;B[od]C[Adios!
])))
(;AW[ma][na][mb][ob][qb][mc][qc][md][oe][qe][pf][rf]AB[oa][pa][qa][ra][nb][rb][nc][oc]C[Black to play.]
(;B[rc]C[Wrong.]
;W[qd]
;B[pb]
;W[pc]C[Black is dead!
])
(;B[pc]C[Not good either.]
;W[rc]LB[pb:A][sb:B]C[A and B are miai])
(;B[qd]C[Wedge!
]
(;W[rd]
;B[rc]
;W[pd]
;B[pc]C[Black is perfectly alive!
])
(;W[rc]
;B[rd]
;W[pd]
;B[pc]C[White cannot attack black.
]
;W[sd]
;B[sb]C[black lives])
(;W[pd]
;B[pc]
;W[rc]
;B[pb]
;W[rd]
;B[sb]C[Black is happy!
])))
(;AW[pa][qb][mc][oc][pc][qc][qd][oe][pe]AB[la][lb][rb][lc][rc][md][rd][me][qe][nf][of][pf][qf]C[Black to play.]
(;B[nb]C[Not good.]
;W[ob]
;B[od]
;W[nc]C[White can live!
])
(;B[ob]C[Not good either.]
;W[nb]
;B[nd]
;W[od]
;B[na]
;W[oa]
;B[nc]
;W[ma]C[White is alive!
])
(;B[od]C[This is a wedging tesuji!
]
(;W[nd]
;B[nb]
;W[ob]
;B[nc]C[White is dead!
])
(;W[ob]C[Be careful!
]
(;B[nd]
;W[mb]C[White is just alive!
])
(;B[nc]
;W[nb]
;B[mb]
;W[na]C[White is satisfied with it!
])
(;B[na]
;W[nd]C[Black's hallucination!
])
(;B[mb]C[Black should play here!
]
;W[nd]
;B[ne]
;W[pd]
;B[nc]
;W[nb]
;B[na]
;W[mc]C[Ko!
Black succeeds!
]))))
(;AW[ma][oa][ra][ob][qb][lc][mc][qc][nd][qd][ne][oe][pe]AB[ka][kb][pb][rb][kc][oc][pc][rc][kd][ld][rd][me][re][mf][nf][of][pf][qf]C[Black to play.]
(;B[pa]C[This is not good.
]
;W[qa]
(;B[nb]
;W[mb]
;B[na]
;W[nc]C[Black is dead!
])
(;B[mb]
;W[nb]
;B[lb]
;W[nc]C[White is happy!
]))
(;B[nb]
;W[mb]C[Black's hane is not working.

])
(;B[mb]C[Wedge!
]
(;W[lb]
;B[nb]
(;W[nc]
;B[pa]C[Black's perfect order of moves
]
;W[qa]
;B[na]
;W[la]
;B[qe]
;W[pd]
;B[md]C[Black wins a race to capture.
])
(;W[pa]
;B[nc]
;W[md]
;B[la]C[White can do nothing.
]))
(;W[nb]
;B[lb]
;W[nc]
;B[qa]C[White cannot live.
])))
(;AW[pa][ra][pb][qb][rb][od][pd][rd][re][pf][qf]AB[mb][ob][sb][oc][sc][nd][sd][ne][se][nf][rf][og][pg][qg][rh]C[Black to play.]
(;B[rc]C[Wrong.]
;W[qd]C[White lives!
])
(;B[oe]C[Not good.]
;W[pe]
;B[qd]
;W[rc]C[White is alive!
])
(;B[qd]C[Wedge!
]
(;W[qc]
;B[rc]
;W[qe]
;B[oe]C[White is dead!
])
(;W[rc]
;B[pc]
;W[qc]
;B[pe]C[White cannot live!
])))
(;AW[ma][ra][jb][mb][ob][rb][ic][mc][pc][qc][jd][md][pd][jf][of][pf][qf][rf][kg][mg][ng]AB[la][lb][qb][lc][rc][ld][nd][qd][rd][le][me][ne][oe][pe][qe]C[Black to play. ]
(;B[oc]C[This is a false tesuji!
]
;W[pb]
;B[nb]
;W[oa]C[Black can do nothiing.
]
;B[qa]
;W[sb])
(;B[nb]C[Wedge!
]
(;W[nc]
;B[oc]
;W[od]
;B[pb]
;W[oc]
;B[oa]C[Cool!
])
(;W[na]
;B[nc]
;W[sb]C[If white plays in this way...
]
;B[pa]C[Diagonal move is wonderful.
]
;W[oa]
;B[oc])
(;W[sb]
;B[na]C[White can live, but so can black!
])))
(;AW[ob][pb][qb][lc][mc][ld][pd][qd][me][ne][oe]AB[oa][jb][lb][mb][nb][kc][kd][rd][le][pe][qe][re][lf][mf][nf][of]C[Black to play.]
(;B[nc]C[Wrong.]
;W[rc]C[White is happy.
])
(;B[rc]C[Wrong.]
;W[nc]
;B[qc]
;W[pc]C[White is very happy.
])
(;B[qc]C[Wedge? Wrong!
]
;W[rc]
;B[rb]
;W[pc]
;B[sc]
;W[nc]C[White is happy!
])
(;B[pc]C[Great Wedge!
]
(;W[oc]
;B[rc]
;W[qc]
;B[nc]C[Now white is dead!
])
(;W[qc]
;B[nc]
;W[rc]
;B[oc]C[White cannot be alive.
])
(;W[rc]C[B should be cautious of this move.
]
(;B[od]C[This is a serious mistake.
]
;W[qc]
;B[oc]
;W[nc]C[...
])
(;B[oc]C[Tranquil!
]
;W[nc]
;B[nd]C[White cannot be alive!
]))))
(;AW[sa][pb][rb][lc][nc][pc][qc][sc][nd]AB[qa][kb][qb][kc][rc][kd][ld][pd][qd][rd][me][ne][oe][re]C[Black to play.]
(;B[oc]C[Wedge!
]
;W[ob]
;B[mb]
(;W[nb]
;B[od]C[White is just dead!
])
(;W[od]
;B[nb]))
(;B[mb]C[Ko variation.]
;W[nb]
;B[pa]C[This is the only move for black]
(;W[oc]
;B[oa]
;W[na]
;B[sd]
;W[ob]C[Ko!
Black's failure.
]
;B[sb]C[White needs to fight the ko here]
;W[ra]
;B[qa]C[like this white is dead])
(;W[oa]C[white can not block]
;B[oc]
;W[ra]
;B[od]LB[qa:B][ob:A]C[A and b are miai])))
(;B[pd]C[This is a game. Black is played by Rui Naiwei 9p, white is Choi Wonyong 5p]
;W[dd]
;B[qp]
;W[dq]
;B[oq]
(;W[qj]
;B[do]
;W[co]
;B[cn]
;W[cp]
;B[fc]
;W[cf]
;B[qh]
;W[qm]
;B[jd]
;W[qf]
;B[pf]
;W[qc]
;B[pc]
;W[qd]
;B[pe]
;W[rf]
;B[oi]LB[hc:B][pg:A]C[This move has many purposes, it aims to put pressure on the two white stones, it enlarges blacks framework, it prevents white from playing at A and black is thinking ahead about the invasion at B. This move is a ladder breaker! But where is the ladder?]
;W[hc]
;B[hd]
(;W[ic]C[So white is forced to play like this.]
;B[id]
;W[jc]
;B[kc]
;W[kb]
;B[gc]
;W[lc]
;B[kd]
;W[mb]
;B[hb]
(;W[ia]C[This is an important jump]
;B[cc]
;W[dc]
;B[cd]
;W[ce]
;B[db]
;W[ci]
;B[me]
;W[gb]
;B[fb]
;W[ga]
;B[jq]
;W[dn]
;B[cj]
;W[dj]
;B[di]
;W[cb]
;B[bb]
;W[ei]
;B[dh]
;W[ch]
;B[ej]
;W[dk]
;B[en]
;W[dm]
;B[dl]C[Wedge, this is todays topic.]
;W[ek]
;B[cm]
;W[em]
;B[el]
;W[fm]
;B[fl]
;W[ck]
;B[gm]
;W[fn]
;B[gn]
;W[eo]
;B[fo]
;W[dp]
;B[fj]
;W[fk]
;B[gk]
;W[cl]
;B[gl]
;W[eh]
;B[om])
(;W[ib]C[Don't play here!]
;B[ia]
;W[jb]
;B[qb]
;W[rb]
;B[ob]C[White needs to live]
;W[gb]
;B[ga]C[and black can make a ko here]))
(;W[id]C[The ladder arises after this wedge!]
;B[ic]C[Black can only play this when the ladder is favourable]
;W[ie]
;B[hb]
;W[jc]
;B[gc]
;W[ib]
;B[hc]
;W[kd]
;B[je]
;W[jf]
;B[ke]
;W[le]
;B[kf]
;W[kg]TR[oi]C[The marked stone shows its strength!]))
(;W[qf]C[This would be more modern])))