(;C[White plays.

Source:
    "In the Beginning", Ikuro Ishigure 8P
    Elementary Go Series, Vol. 1]AB[cd][dc][ed][df][hd][kc][nc][dq][ep][cp][co][hq][ip][jp][rr][rq][qp][qo][ro][rm][qm][pm][pn]AW[ce][cg][dg][cj][cn][dn][do][kq][jq][kp][qn][rn][po][on][no][pp][qq][qr][pr][oq][pc][qg][pd]

(;W[qi]C[The board has already been fairly well divided up and both sides' groups are strong, so White should take the last big point of the opening here.  The 1 point extension may seem narrow, but White should play solidly while approaching Black's thickness below.];B[qe]C[Less obvious is that White's move also defends the upper right corner, as this sequence shows.];W[pe];B[qb];W[pb];B[qf];W[pf];B[rg];W[rh]TR[qi]C[Note how White's marked stone supports this blocking hane.];B[pg];W[qh]
;B[rc]C[Question:  Can Black live?];W[qc];B[rb];W[rd]C[Answer:  No!])
(;W[be]LB[bn:a][dp:b][fn:c][fg:d]C[If White plays on the left side here (or at A, B, C, D), then ...];B[qe]C[... Black can invade here.]
(;W[pe];B[qb];W[pb]C[White blocks, because if Black connects here, White would take a big loss in the corner.];B[qf]C[But now Black has this instructive simple living sequence.];W[pf];B[rg];W[qh];B[rh];W[qi];B[rc]C[In some circumstances, White could use the resulting strong outside thickness to counterattack any nearby weak groups.  But in this position, Black's groups are all settled, so White cannot afford this loss of corner territory.])
(;W[pf]C[White can try this diagonal connection, but ...];B[rg]C[... Black has another instructive simple sequence here.];W[rh];B[rf];W[qh];B[rc];W[qb];B[rb]
(;W[ra]C[White can prevent the invading group from making 2 eyes inside,  but ...];B[pe]C[... Black can push to run out or cut off White's top stones.])
(;W[nd]C[Better.];B[ra];W[mc]LB[pe:a]C[But now Black has made life and still threatens the push and cut, starting with A.]))))